Published research papers
1) Pascoal, A., Oliveira, J.M., Pereira, A.P., Féas, X., Anjos, O., Estevinho, L.M.
Influence of fining agents on the sensorial characteristics and volatile composition of mead
(2017) Journal of the Institute of Brewing, 123 (4), pp. 562-571.
Abstract
Mead, one of the oldest fermented drinks, is derived from the fermentation of diluted honey by yeasts. In the context of wine production, several procedures are applied to stabilize the beverage and to improve its organoleptic properties. This study aims to evaluate the impact of adding fining agents on the production of mead. In general, the best results were obtained for the samples containing just one fining agent instead of two combined. However, the best performance was obtained for the combined fining agents (bentonite + gelatine + egg albumin). Tannins decreased significantly the content of volatile compounds. On the other hand, silica appears to be the best fining agent, resulting in the lowest loss of volatile compounds. Thirty-six volatile compounds were determined by gas chromatograph–flame ionization detector and gas chromatography–mass spectrometry, including alcohols (42.5%), carbonyl compounds (40.4%), acetates (14.4%) and esters (1.8%). Eleven volatile compounds had odour activity values >1, representing those with a major impact on the aroma of mead. Significant differences (p < 0.05) were found in 10 volatile compounds independently to the type of treatment used and no differences (p > 0.05) were observed for remaining compounds. Copyright © 2017 The Institute of Brewing & Distilling. Copyright © 2017 The Institute of Brewing & Distilling
Author Keywords
fining agents; mead; odour activity values; sensorial analysis; volatile compounds
2) Feás, X., Pacheco, L., Iglesias, A., Estevinho, L.M.
Use of propolis in the sanitization of lettuce
(2014) International Journal of Molecular Sciences, 15 (7), pp. 12243-12257.
Abstract
The present study aimed to determine the effectiveness of propolis in reducing the microbial load in ready-to-eat (RTE) and fresh whole head (FWH) lettuces (Lactuca sativa L.) type Batavia. Two sanitizing solutions were employed: sodium hypochlorite (SH) and propolis (PS), during 15 and 30 min. Tap water (TW) was used as a control. Regarding the mean reduction on aerobic mesophiles, psychrotrophic and fecal coliforms, the SH and PS treatments showed the same pattern of variation. In all cases, PS was slightly more effective in the microbiological reduction in comparison with commercial SH. Reductions between two and three log cycles were obtained with PS on aerobic mesophiles and psychrotrophic counts. The information obtained in the present study can be used to evaluate the potential use of propolis as product for sanitizing other vegetables and for developing other food preservation technologies, with impact on human health. © 2014 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Lettuce; Microbiological safety; Propolis; Sanitization; Sodium hypochlorite
3) Vázquez-Tato, M.P., Mena-Menéndez, A., Feás, X., Seijas, J.A.
Novel microwave-assisted synthesis of the immunomodulator organotellurium compound ammonium trichloro(dioxoethylene-o,o')tellurate (AS101)
(2014) International Journal of Molecular Sciences, 15 (2), pp. 3287-3298.
Abstract
Ammonium trichloro[1,2-ethanediolato-O,O']-tellurate (AS101) is the most important synthetic Te compound from the standpoint of its biological activity. It is a potent immunomodulator with a variety of potential therapeutic applications and antitumoral action in several preclinical and clinical studies. An experimental design has been used to develop and optimize a novel microwave-assisted synthesis (MAOS) of the AS101. In comparison to the results observed in the literature, refluxing Te(IV) chloride and ethylene glycol in acetonitrile (Method A), or by refluxing Te(IV) chloride and ammonium chloride in ethylene glycol (Method B), it was found that the developed methods in the present work are an effective alternative, because although performance slightly decreases compared to conventional procedures (75% vs. 79% by Method A, and 45% vs. 51% by Method B), reaction times decreased from 4 h to 30 min and from 4 h to 10 min, by Methods A and B respectively. MAOS is proving to be of value in the rapid synthesis of compounds with new and improved biological activities, specially based on the benefit of its shorter reaction times. © 2014 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Ammonium trichloro[1,2-ethanediolato-O,O']-tellurate; Antitumoral; AS101; Microwave irradiation; Tellurium
4) Seijas, J.A., Crecente-Campo, J., Feás, X., Vázquez-Tato, M.P.
Microwave assisted synthesis, crystal structure and modelling of cytotoxic dehydroacetic acid enamine: A natural alkaloid from Fusarium incarnatum (HKI0504)
(2014) RSC Advances, 4 (33), pp. 17054-17059.
Abstract
A novel, fast and efficient method for the synthesis of (3E)-3-(1-aminoethylidene)-6-methyl-3,4-dihydro-2H-pyran-2,4-dione, a natural antiproliferative and cytotoxic product isolated from Fusarium incarnatum (HKI0504), was developed from dehydroacetic acid and urea under solvent-free microwave irradiation. The analysis of the co-crystal structure revealed an asymmetric unit formed by a pair of molecules. Each molecule is joined by two different hydrogen bonds to another two molecules, ordered as four-unit clusters linked by π-stacking, assembled in a brick like layered structure in a set of parallel walls. Besides, the preferred tautomer for crystal structure is the enamine form. This is corroborated by computational NBO analysis, outlining the contribution of enamine resonance and modelling the non-covalent interactions involved by means of Hirshfeld surfaces and G09 counterpoise calculations. © 2014 the Partner Organisations.
5) Pascoal, A., Rodrigues, S., Teixeira, A., Feás, X., Estevinho, L.M.
Biological activities of commercial bee pollens: Antimicrobial, antimutagenic, antioxidant and anti-inflammatory
(2014) Food and Chemical Toxicology, 63, pp. 233-239.
Abstract
Bee pollen is considered, since memorable times, a good source of nourishing substances and energy. The present study aimed to evaluate the biological activities of eight commercial bee pollens purchased from the market. The origin of sample A was not specified in the labeling; samples B, C, D and G were from Portugal and the remaining were from Spain. The sample E presented the highest value of phenolics (32.15. ±. 2.12. mg/g) and the H the lowest (18.55. ±. 095. mg/g). Sample C had the highest value of flavonoids (10.14. ±. 1.57. mg/g) and sample H the lowest (3.92. ±. 0.68. mg/g). All the samples exhibited antimicrobial activity, being Staphylococcus aureus the most sensitive and Candida glabrata the most resistant of the microorganisms studied. All the samples exhibited antimutagenic activity, even though some samples were more effective in decreasing the number of gene conversion colonies and mutant colonies. Regarding the antioxidant activity, assessed using two methods, the more effective was sample B. The anti-inflammatory activity, assessed using the hyaluronidase enzyme, was highest in samples B and D. Pearson's correlation coefficients between polyphenols, flavonoids, antioxidant activity and antimicrobial activity were computed. It was also performed a discriminant analysis. © 2013 Elsevier Ltd.
Author Keywords
Antimicrobial activity; Antimutagenicity; Antioxidant activity; Bee pollen; Bioactive compounds; Inflammation
6) Pascoal, A., Feás, X., Dias, T., Dias, L.G., Estevinho, L.M.
The Role of Honey and Propolis in the Treatment of Infected Wounds
(2014) Microbiology for Surgical Infections: Diagnosis, Prognosis and Treatment, pp. 221-234.
Abstract
Honey as a natural, unprocessed and easily digested food is a valuable nutritive product for children, athletes and convalescents. It has been used in ethno-medicine since the prehistoric times, and recently in the treatment of burns, healing wounds, chronic wounds, gastrointestinal disorders, asthma, skin ulcers, cancer, oncology, and as an antioxidant and antimicrobial agent. Propolis is prepared by bees of the Apis mellifera species, using resinous substances collected from various plants, and has been reported to possess pharmacological properties, such as antibiotic, anti-neoplastic, anti-inflammatory, anti-diarrheatic, antimicrobial, antiviral, antioxidant, hepatoprotective, cariostatic, antitumoral, anti-ulcerus, immunostimulator, antineurodegenerative, antituberculosis and anti-HIV-1 activity. The biological activity of these products is mainly attributed to phenolic compounds, such as flavonoids. In this context, the topical application of beehive products, particularly honey and propolis, has great potential in the treatment of several injuries and diseases, since it would improve patients' outcome without undesirable side effects. This chapter aims to present information from published studies regarding the beneficial effects of those products on a range of medical conditions and infected wounds. © 2014 Elsevier Inc. All rights reserved.
Author Keywords
Antimicrobial activities; Honey; Infected wounds and healing; Phenolic compounds; Propolis
7) Iglesias, A., Pascoal, A., Choupina, A.B., Carvalho, C.A., Feás, X., Estevinho, L.M.
Developments in the fermentation process and quality improvement strategies for mead production
(2014) Molecules, 19 (8), pp. 12577-12590.
Abstract
Mead is a traditional alcoholic drink derived from the fermentation of diluted honey in the presence of appropriate yeast. Its modern production, in general terms, involves the addition of nutrients to initial diluted honey, pasteurization, yeast inoculation, fermentation and removal of impurities. Undesirable events along the process have been reported; among them, we highlight: delayed or arrested fermentations, modified and unpleasant sensory and quality parameters of the final product. These problems have been linked to the inability of yeasts to accomplish their role in extreme growth conditions. Emphasis has also been placed on the long fermentation times required, ranging from weeks to months, particularly when traditional procedures are applied and when the honey concentration is low. A series of alterations to the must and technological changes have been proposed in order to optimize the mead production process. In this context, this review examines the evidence that aims to improve meads' quality and make the production process easier and more efficient, by clarifying the source of unexpected events, describing the implementation of different fermentative microorganisms and using new methodologies. © 2014 by the authors.
Author Keywords
Fermentation progress; Fermentative microorganisms; Honey; Mead production; Quality procedures
8) Hosseini, S.V., Hamzeh, A., Moslemi, M., Lashkan, A.B., Iglesias, A., Feás, X.
Effect of delayed icing on biogenic amines formation and bacterial contribution of iced common carp (cyprinus carpio)
(2013) Molecules, 18 (12), pp. 15464-15473.
Abstract
The variation of six biogenic amines (BAs) and total viable count (TVC) in common carp (Cyprinus carpio) stored in ice with 0, 4 and 8 h delay before icing was evaluated in a period of 4 days. Delayed icing led to significant (p < 0.05) increases in TVC throughout the period of storage and showed a good correlation with BAs content. The obtained data showed that putrescine and cadaverine were predominant in all samples and it was indicated that they could be proper indicators to determine the carp quality. Spermidine and spermine increased slightly toward the end of storage and the levels of dangerous BAs (histamine and tyramine) were under the limit over the period. As a result, it is indicated that delaying time affects on formation of BAs and the effect in samples with 8 h delay was significantly (p < 0.05) more than those with 0 and 4 h delay. © 2013 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Biogenic amines; Carp; Delayed icing; Fish; Storage
9) Feás, X., Iglesias, A., Rodrigues, S., Estevinho, L.M.
Effect of Erica sp. honey against microorganisms of clinical importance: Study of the factors underlying this biological activity
(2013) Molecules, 18 (4), pp. 4233-4246.
Abstract
This study aimed to determine the factors (phenolic compounds, flavonoids, sugars or H2O2) that contribute the most to the antimicrobial activity of heather honey samples against four yeasts and four bacteria with medical importance. To discard the effect of H2O 2 in the antimicrobial activity, catalase was added. To evaluate the osmotic pressure's effect, artificial honey was also used. Phenolic compounds and flavonoids were determined and Pearson's correlation analysis was performed to assess whether these correlated with antimicrobial activity. The amount of phenolic compounds ranged from 630.89 ± 5.21 GAE kg-1 to 718.92 ± 4.41 GAE kg-1, while the flavonoids varied between 450.72 ± 5.67 CAE kg-1 and 673.98 ± 4.33 CAE kg -1. For the bacteria, the minimum inhibitory concentration (MIC) of the honey without catalase ranged from 1.01 ± 0.50% to 10.00 ± 4.72% and was between 2.00 ± 0.94% and 13.27 ± 5.23% for honey with catalase. Concerning the yeasts, the MICs was between 13.16 ± 4.08% and 20.00 ± 5.09% for honey without catalase and between 14.95 ± 4.16% and 25.67 ± 5.50% for honey with catalase. The elucidation of the antimicrobial factors and action mechanisms is essential for the correct use of honey in therapeutic applications. © 2013 by the authors.
Author Keywords
Antibacterial properties; Antifungal properties; Heather honey; Hydrogen peroxide; Polyphenols; Sugars
10) Feás, X., Estevinho, L.M., Salinero, C., Vela, P., Sainz, M.J., Vázquez-Tato, M.P., Seijas, J.A.
Triacylglyceride, antioxidant and antimicrobial features of virgin camellia oleifera, C. reticulata and C. sasanqua oils
(2013) Molecules, 18 (4), pp. 4573-4587.
Abstract
Virgin oils obtained from seeds of Camellia oleifera (CO), Camellia reticulata (CR) and Camellia sasanqua (CS) were studied for their triacylglyceride composition, antioxidant and antimicrobial activities. Levels of fatty acids determined by 1H-nuclear magnetic resonance analysis were similar to those reported for olive oils (82.30%-84.47%; 5.69%-7.78%; 0.26%-0.41% and 8.04%-11.2%, for oleic, linoleic, linolenic and saturated acids, respectively). The CR oil showed the best antioxidant potential in the three in vitro models tested. With regard to EC50 values (μg/mL), the order in DPPH radical-scavenging was CR (33.48) < CO (35.20) < CS (54.87). Effectiveness in reducing power was CR (2.81) < CO (3.09) < CS (5.32). IC50 for LPO inhibition were 0.37, 0.52 and 0.75 μg/mL for CR, CO and CS, respectively. All the oils showed antimicrobial activity, and exhibited different selectivity and MICs for each microorganism tested (E. coli, B. cereus and C. albicans). B. cereus was the less sensitive species (MIC: 52.083 ± 18.042 for CO; 41.667 ± 18.042 for CR; 104.167 ± 36.084 for CS mg/mL) and the E. coli was the most sensitive to camellia oil's effect. The standard gentamicin presented higher MIC for E. coli (4.2) than the CR (MIC= 2.6) and CO (MIC = 3.9) oils. © 2013 by the authors.
Author Keywords
Antimicrobial activity; Antioxidant potential; Camellia; Oil; Triacylglyceride
11) Estevinho, M., Vázquez-Tato, M., Seijas, J., Feás, X.
Palynological, physicochemical, and microbiological attributes of organic lavender (Lavandula stoechas) honey from Portugal
(2013) Acta Alimentaria, 42 (1), pp. 36-44.
Abstract
At the present time, the quality, integrity, sanitation, and nutritional value of honeys receive attention on an international level due to the increasing content of chemicals in the aforementioned matrix. The present study aims to characterize organic honey (n=73) from Northeast Portugal, with respect to floral nectar origin, physicochemical parameters, microbial safety, and commercial quality. All organic honey samples can be classified as monofloral lavender (Lavandula stoechas L.), exceed in quality the international physicochemical standards, and show low microbiological counts (yeast, moulds, and aerobic mesophiles), with negative results in respect to faecal coliforms, Salmonella, and sulphite-reducing clostridia. Correlating the palynological, physicochemical, and microbiological results is necessary in order to check the authenticity, quality, and sanitation of honey.
Author Keywords
honey; microbiological analysis; organic; physicochemical attributes
12) Salinero, C., Feás, X., Mansilla, J.P., Seijas, J.A., Vázquez-Tato, M.P., Vela, P., Sainz, M.J.
1H-nuclear magnetic resonance analysis of the triacylglyceride composition of cold-pressed oil from Camellia japonica.
(2012) Molecules (Basel, Switzerland), 17 (6), pp. 6716-6727.
Abstract
Camellia japonica (CJ) has oil-rich seeds, but the study of these oils has received little attention and has mainly focused only on their health properties. In the present work the relative composition of the fatty acid (FA) components of the triglycerides in cold-pressed oil from CJ is studied by 1H-NMR. The results obtained were: 75.75%, 6.0%, 0.17% and 18.67%, for oleic, linoleic, linolenic and saturated FA respectively. Levels of C 18 unsaturated FA found in CJ oil were similar to those reported for olive oils. We also checked the possibility of using 13C-NMR spectroscopy; however, the results confirmed the drawback of 13C over 1H-NMR for the study of FA components of CJ triglycerides due to its low gyromagnetic ratio and its very low natural abundance.
13) Feas, X., Vazquez-Tato, M.P., Estevinho, L., Seijas, J.A., Iglesias, A.
Organic bee pollen: Botanical origin, nutritional value, bioactive compounds, antioxidant activity and microbiological quality
(2012) Molecules, 17 (7), pp. 8359-8377.
Abstract
Organic bee pollen (BP, n = 22) harvested from the Douro International Natural Park (DINP, Portugal) was studied. Nine botanical families were found in the mixture of the samples. The water activity and pH ranged 0.21-0.37 and 4.3-5.2, respectively. The BP analyses averaged 67.7% carbohydrates, 21.8% crude protein, 5.2% crude fat and 2.9% ash. The energy ranged from 396.4 to 411.1 kcal/100 g. The principal fatty acid found was linolenic, followed by linoleic acid, palmitic acid and oleic acid. The phenolic and flavonoid contents varied from 12.9 to 19.8 mg of gallic acid equivalents/g of extract and from 4.5 to 7.1 mg of catechin equivalents/g of extract, respectively. The scavenger activity and β-carotene bleaching assays values (EC 50) were 3.0 μ 0.7 mg/mL and 4.6 mg/mL μ 0.9 mg/mL, respectively. E. coli, sulphite-reducing Clostridia, Salmonella and S. aureus were not found. Since there are studies indicating appreciable differences among BPs from different regions, the full characterization of BP from diverse origins still appears to be a sound research priority in order to obtain reliable data about this beehive product. © 2012 by the authors.
Author Keywords
Antioxidant capacity; Bee pollen; Bioactive compound; Fatty acids; Microbiological safety; Organic food
14) Iglesias, A., Feás, X., Rodrigues, S., Seijas, J.A., Vázquez-Tato, M.P., Dias, L.G., Estevinho, L.M.
Comprehensive study of honey with protected denomination of origin and contribution to the enhancement of legal specifications
(2012) Molecules, 17 (7), pp. 8561-8577.
Abstract
In this study the characterization of a total of 60 honey samples with Protected Denomination of Origin (PDO) collected over three harvests (2009-2011, inclusive), from the Northeast of Portugal was carried out based on the presence of pollen, physicochemical and microbiological characteristics. All samples were found to meet the European Legislation, but some didn′t meet the requirements of the PDO specifications. Concerning the floral origin of honey, our results showed the prevalence of rosemary (Lavandula pedunculata) pollen. The microbiological quality of all the analyzed samples was satisfactory, since fecal coliforms, sulfite-reducing clostridia and Salmonella were absent, and molds and yeasts were detected in low counts. Significant differences between the results were studied using one-way analysis of variance (ANOVA), followed by Tukey′s HSD test. The samples were submitted to discriminant function analysis, in order to determine which variables differentiate between two or more naturally occurring groups (Forward Stepwise Analysis). The variables selected were in this order: diastase activity, pH, reducing sugars, free acidity and HMF. The pollen spectrum has perfect discriminatory power. This is the first study inwhich a honey with PDO was tested, in order to assess its compliance with the PDO book of specifications. © 2012 by the authors.
Author Keywords
Honey; Microbiological; Palynological; Physicochemical; Protected Denomination of Origin
15) Salinero, C., Feás, X., Pedro Mansilla, J., Seijas, J.A., Pilar Vázquez-Tato, M., Vela, P., Sainz, M.J.
1H-nuclear magnetic resonance analysis of the triacylglyceride composition of cold-pressed oil from Camellia japonica
(2012) Molecules, 17 (6), pp. 6716-6727.
Abstract
Camellia japonica (CJ) has oil-rich seeds, but the study of these oils has received little attention and has mainly focused only on their health properties. In the present work the relative composition of the fatty acid (FA) components of the triglycerides in cold-pressed oil from CJ is studied by 1H-NMR. The results obtained were: 75.75%, 6.0%, 0.17% and 18.67%, for oleic, linoleic, linolenic and saturated FA respectively. Levels of C 18 unsaturated FA found in CJ oil were similar to those reported for olive oils. We also checked the possibility of using 13C-NMR spectroscopy; however, the results confirmed the drawback of 13C over 1H-NMR for the study of FA components of CJ triglycerides due to its low gyromagnetic ratio and its very low natural abundance. © 2012 by the authors.
Author Keywords
13C-NMR; 1H-NMR; Camellia japonica; Nuclear magnetic resonance; Oil; Triacylglycerides
16) Silva, J.C., Rodrigues, S., Feás, X., Estevinho, L.M.
Antimicrobial activity, phenolic profile and role in the inflammation of propolis
(2012) Food and Chemical Toxicology, 50 (5), pp. 1790-1795.
Abstract
Nowadays a great amount of information regarding chemical and biological aspects of bee products is available in the literature, but few data on its therapeutic uses are found. The aim of this study was to evaluate the phenolic profile, the in vitro antimicrobial activity and effect in the hyaluronidase enzyme (widely related with the inflammation process) of propolis harvested in Portugal. The efficacy of three extracts (hydro-alcoholic, methanolic and aqueous) was also compared. It was chosen the hydro-alcoholic extract, because this was the most effective for extracting phenolic compounds. The antimicrobial activity was accessed in Gram-positive and Gram-negative bacteria and yeasts, isolated from different biological fluids and the results were then compared with the obtained for reference microorganisms. The propolis from Bragança was the one that possessed the highest polyphenols' content. The sample from Beja showed the less significant inhibition of the hyaluronidase enzyme. Concerning the antimicrobial activity, Candida albicans was the most resistant and Staphylococcus aureus the most sensitive. The reference microorganisms were more sensitive than the ones isolated from biological fluids. © 2012 Elsevier Ltd.
Author Keywords
Antimicrobial activity; Hyaluronidase; Inflammation; Phenolic compounds; Propolis
17) Estevinho, M.L., Feás, X., Seijas, J.A., Vázquez-Tato, M.P.
Physicochemical and pollen analysis of Local honeys from the Lima Valley (Portugal)
(2012) Electronic Journal of Environmental, Agricultural and Food Chemistry, 11 (3), pp. 214-221.
Abstract
An evaluation was done on the physicochemical quality of nineteen (n=19) Apis mellifera honeys produced in the Lima Valley, Portugal. The rural landscape of the Lima Valley is valuable in social, environmental and economic terms and its conservation and preservation are essential. The evaluated physicochemical characteristics were: moisture, ash, electrical conductivity, pH, hydroxymethylfurfural (HMF), free acidity, apparent sucrose, reducing sugars and diastase activity. All honey samples met the International physicochemical quality standards. A short study of pollen source was done by acetolisis method. The families Fabaceae and Rosaceae were found with 6 and 2 pollen types each respectively. The most important pollen source is Erica, moreover two samples are listed as Erica monofloral honey.
Author Keywords
Erica; Honey; Lima valley; Physicochemical characteristics; Pollen analysis; Portugal; Quality
18) Estevinho, L.M., Rodrigues, S., Pereira, A.P., Feás, X.
Portuguese bee pollen: Palynological study, nutritional and microbiological evaluation
(2012) International Journal of Food Science and Technology, 47 (2), pp. 429-435.
Abstract
Bee pollen is one of the richest and purest natural foods, used in the folk medicine, clinical practices, and food and pharmaceutical industries. This work aims to characterise, for the first time in Portugal, the palynological origin, nutritional value and microbiological safety of this beehive product. It identified ten botanical families, and the more frequent were Boraginaceae and Ericaceae. We have evaluated the water content, a w, pH, reducing sugars, ash, carbohydrate, proteins, lipids, fatty acids and energy. The microorganisms studied were the aerobic mesophiles, moulds and yeasts, faecal coliforms, Escherichia coli, Staphylococcus aureus, Salmonella and sulphite-reducing clostridia. The studied pollens are nutritionally well balanced, and contain high levels of moisture, proteins, fat, energy, ash, carbohydrates, reducing sugars, essential n-3 fatty acids and good ratios of polyunsaturated fatty acids (PUFA)/saturated fatty acids. In fact, the PUFA represent 66% of the total fatty acids. The samples had good microbiological quality, as none of the samples had toxigenic species. © 2011 Institute of Food Science and Technology.
Author Keywords
Bee pollen; Fatty acids; Microbiological safety; Nutrients
19) Estevinho, L.M., Feás, X., Seijas, J.A., Pilar Vázquez-Tato, M.
Organic honey from Trás-Os-Montes region (Portugal): Chemical, palynological, microbiological and bioactive compounds characterization
(2012) Food and Chemical Toxicology, 50 (2), pp. 258-264.
Abstract
At the present time, the quality, integrity, sanitation and nutritional value of honeys receive attention on an international level due to the increasing content of chemicals in the aforementioned matrix. This work was conducted to evaluate the quality of 75 organic honey samples from the Trás-Os-Montes region (Portugal). Mean values obtained for physico-chemical parameters were: pH 3.7; 15.6% moisture; 0.26mS/cm electrical conductivity; 0.25% ash; 1.1mg/kg HMF; 15.3 Gothe diastase activity; 40.3meq/kg free acidity; 67.8% invert sugars and 2.7% apparent sucrose. All honey samples can be classified as monofloral Erica sp., as showed by pollen features. The amounts of phenols and flavonoids in the samples were also determined. In respect to sanitary quality (fecal coliforms) and safety (sulfite-reducing clostridia and Salmonella), all organic honey samples were negative. Furthermore, yeast and molds were detected in low counts, with mean values obtained of 5.5cfu/g and the value of total aerobic mesophiles obtained from honeys was established in 1.3×10 2cfu/g±7.5×10 1cfu/g. The levels of flavonoids had a stronger impact on both mesophiles (p=0.0004) and molds (p=0.0138) than the sucrose concentration (p=0.001 and 0.0278; respectively). The results reported in this study should be introduced in the organic honey label, and may help beekeepers, the industry, researchers and consumers better understand honey properties. © 2011 Elsevier Ltd.
Author Keywords
Bioactive compounds; Erica sp.; Honey; Microbiological analysis; Organic; Physico-chemical analysis
20) Nogueira, C., Iglesias, A., Feás, X., Estevinho, L.M.
Commercial bee pollen with different geographical origins: A comprehensive approach
(2012) International Journal of Molecular Sciences, 13 (9), pp. 11173-11187.
Abstract
Since the primordial of humanity, pollen has been considered a good source of nutrients and energy. Its promising healing properties have also been referred to. The present study aimed to characterize, for the first time, eight commercial pollens from Portugal and Spain available on the market studying the legislation on labeling, pollinic origin, physicochemical and microbiological analyses and identification of yeasts. Eleven botanical families were found amongst the samples. The most abundant family and the most dominant pollen was Cistaceae. The moisture content, ash, aw, pH, reducing sugars, carbohydrates, proteins, lipids and energy were analyzed and the specific parameters were within the specifications required by some countries with legislation regarding these parameters. Microbiologically commercial pollen showed acceptable safety for the commercial quality and hygiene. All samples showed negative results for toxigenic species. The microorganisms studied were aerobic mesophiles, yeasts and moulds, coliforms, Escherichia coli, Staphylococcus aureus, Salmonella and sulfite-reducing Clostridium. During the work, six yeasts species were isolated from pollen, with Rhodotorula mucilaginosa being the most abundant, as it was present in four samples. © 2012 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Bee pollen; Labeling rules; Microbiological characterization; Physicochemical characterization; Pollinic analysis
21) Feás, X., Estevinho, M.L.
A Survey of the in vitro antifungal activity of heather (Erica Sp.) Organic honey
(2011) Journal of Medicinal Food, 14 (10), pp. 1284-1288.
Abstract
Monofloral heather (Erica sp.) honey samples (n=89), harvested in Portugal according to European organic beekeeping rules, were analyzed to test their antifungal effect against Candida albicans, Candida krusei, and Cryptococcus neoformans. A synthetic honey solution was also tested to determine antifungal activity attributable to sugars. The specific growth rate (μ) values showed that growth of all the yeasts was reduced in the presence of honey. The honey concentration (% wt/vol) that inhibited 10% of the yeast growth (X min) was 13.5% for C. albicans, 20.5% for C. krusei, and 17.1% for C. neoformans. The respective concentrations of heather honey and synthetic honey in the C. krusei culture medium above 60% (wt/vol) that inhibited 90% of the yeast growth (X max) and X min, respectively, were established, whereas C. albicans and C. neoformans were more resistant because X max values were not reached over the range tested (10-60%, wt/vol). Heather honey might be tapped as a natural resource to look for new medicines for the treatment of mycotic infections. Further studies are now required to demonstrate if this antifungal activity has any clinical application. © 2011 Mary Ann Liebert, Inc.
Author Keywords
antifungal effects; Candida albicans; Candida krusei; Cryptococcus neoformans; Erica species; honey
22) Estevinho, M.L., Afonso, S.E.T., Feás, X.
Antifungal effect of lavender honey against Candida albicans, Candida krusei and Cryptococcus neoformans
(2011) Journal of Food Science and Technology, 48 (5), pp. 640-643.
Abstract
Monofloral lavender honey samples (n=30), were analyzed to test antifungal effect against Candida albicans, Candida krusei, and Cryptococcus neoformans. The specific growth rates (μ) showed that all the yeast growths were reduced in the presence of honey. The honey concentration (% w/v) that inhibited 10% of the yeasts growth (Xmin) ranged from 31.0% (C. albicans), 16.8% (C. krusei) and 23.0% (C. neoformans). A synthetic honey solution was also tested to determine antifungal activity attributable to sugars. The presence of synthetic honey in the C. krusei culture medium at concentrations above 58.0% (w/v) was established as Xmin, while C. albicans and C. neoformans were more resistant, since Xmin values were not reached over the ranged tested (10-60%, w/v). What the data suggests is that the component in the lavender honey responsible for the observed antifungal in vitro properties is not sugar based. Honey might be tapped as a natural resource to look for new medicines for the treatment of mycotic infections. This could be very useful, onsidering the increasing resistance of antifungals. It should be noticed that this is the first study concerning the effect of lavender honey on the growth of pathogenic yeasts. © 2011 Association of Food Scientists & Technologists (India).
Author Keywords
Antifungal; Candida albicans; Candida krusei; Cryptococcus neoformans; Honey; Lavender
23) Cerqueira, J.O.L., Feás, X., Iglesias, A., Pacheco, L.F., Araújo, J.P.P.
Morphological traits in Portuguese Bordaleira de Entre Douro e Minho sheep: Divergence of the breed
(2011) Animal Production Science, 51 (7), pp. 635-641.
Abstract
Production of the autochthonous Portuguese sheep breed Bordaleira de Entre Douro e Minho (BEDM) is directly associated with the concept of sustainable agriculture. This concept focuses on the adaptation of animal populations to adverse environmental conditions, high biological efficiency and traditional management. Native BEDM sheep can be divided into the following two types on the basis of their geographic location in Portugal and how they are managed: the Vrzea, which is found mainly in the lower Entre Douro e Minho region, and the Mountain type, which traditionally prefers common areas. In the present work, we analysed records of liveweight, 15 body measurements and eight indexes of the BEDM sheep, to explore the ability to distinguish different characteristics between BEDM sheep populations. The records that were obtained and analysed by principal component analysis for 412 BEDM sheep (68 males and 344 females) included the following: heights at withers (HW), at back (HB), at rump (HR) and at chest (HC); lengths of trunk (LT), of rump (LR), of head (LH) and of perineum (LP); widths of head (WH), of chest (WC), of biiliac (WBIIL) and of biischiatic (WBIIS); perimeters of the shin (PS), thorax (PT), and abdomen (PA); and finally indexes such as cephalic index (CI), thoracic index (TI), pelvic index (PI), body index (BI), relative chest depth index (RDCI), lateral corporal index (LCI), relative shin thickness index (RTSI) and dactylthoracic index (DTI). The Vrzea BEDM was morphologically superior to the Mountain variety, with this superiority more evident in females. Height measurements, especially HW in adult females, provided an excellent measurement reference for biometrical breed studies. Functional index values confirmed the BEDM Mountain variety's appropriateness for mountainous regions. Relationships among body measurements suggested that the breed standard needed to be updated. The research presented here was used by the Portuguese Ministery to split BEDM into two new breeds; the traditional variety called Vrzea now represents the new BEDM breed, whereas the Mountain variety represents the new Churra do Minho breed. © CSIRO 2011.
Author Keywords
Churra do Minho breed; Portugal
24) Gomes, T., Feás, X., Iglesias, A., Estevinho, L.M.
Study of organic honey from the northeast of Portugal
(2011) Molecules, 16 (7), pp. 5374-5386.
Abstract
Concerns about traces of numerous toxic substances and authenticity have prompted consumer demand for honey that is certified as organic, based on strict ecological, natural principles and traceability. The present study aims to characterize organic honey samples (n = 73) from Northeast Portugal, with respect to floral nectar origin, physicochemical parameters and microbial safety. The phenols and flavonoids contents, often referred to as responsible for honey's bioactive properties, were also assessed. All organic honey samples were classified as monofloral lavender (Lavandula sp.), exceeded in quality the international physicochemical standards and showed low microbiological counts (yeast, moulds and aerobic mesophiles), with negative results in respect to fecal coliforms, Salmonella and sulphite-reducing Clostridium spp. Correlation of the palynological, physicochemical and microbiological results is necessary to check the authenticity, quality and sanitation of honey. Although not required by international legislation, results of those assessments provide a complete outlook and elucidation of the organic honey's properties, which could promote its valorisation. © 2011 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Honey; Lavender; Microbiology; Organic foods; Phenolic compounds; Physicochemical properties
25) Iglesias, A., De Jesus, C., Cantalapiedra, J.J., Sanchez, L., Feas, X.
Cryopreservation of semen of celta breed boars
(2011) Indian Veterinary Journal, 88 (7), pp. 28-29.
Abstract
The data of fresh semen characteristics, the possible effects of freezing on sperm viability, and seminal variables due to changes in annual cycle were studied in the autochthonous Celta breed (NW Spain). In fresh semen, the following parameters were computed: ejaculate volume (202±26.6 ml), sperm motility (82.1±1.2 %), sperm concentration (401±35.1x106 sperm/ml), normal acrosomes (86.8±6.3 %), distal cytoplasmic droplets (12.1±6.1 %) and abnormal sperm cells (26.1±9.8 %). The ejaculate volume was affected by the month, maximum temperature, minimum temperature, minimum relative humidity and the interaction between maximum temperature and minimum relative humidity. Freezing semen had a significant effect on spermatic characteristics, even though viability (57.64±10.1 %), motility (73.3±3.2 %) remained at acceptable levels.
26) Morais, M., Moreira, L., Feás, X., Estevinho, L.M.
Honeybee-collected pollen from five Portuguese Natural Parks: Palynological origin, phenolic content, antioxidant properties and antimicrobial activity
(2011) Food and Chemical Toxicology, 49 (5), pp. 1096-1101.
Abstract
The aim of this study was to determine the palynological origin, phenolic content, antioxidant and antimicrobial properties of pollen from five Portuguese Natural-Parks [Parque Nacional Peneda Gerês (PNPG); Parque Natural do Montesinho (PNM); Parque Natural do Alvão (PNA); Parque Natural da Serra da Estrela (PNSE) and Parque Natural do Douro Internacional (PNDI)]. Eight families were found in the mixture of bee pollen: Rosaceae, Cistaceae, Boraginaceae, Asteraceae, Fagaceae, Ericaeae, Myrtaceae and Fabaceae. The phenolic compounds content, determined by the Folin-Ciocalteu method, varied between 10.5 and 16.8mg of gallic acid equivalents/g of extract (mg GAE/g) found in bee pollen from PNM and PNDI, respectively. The free radical scavenging measured showed the highest effective extract - PNM with EC50 2.16, followed by PND with 2.24mg/mL. In the β-carotene bleaching assay the same behaviour as in the DPPH method was verified. We also verified that the presence of pollen differentially affected the growth of bacteria Gram-positive, Gram-negative and yeasts under study, depending this on the microorganism and the pollen used. This is an important study since, as far we know, it is the first time that Portuguese bee pollen from Natural Parks was studied, and their characterization can increase their economic value. © 2011.
Author Keywords
β-Carotene bleaching assay; Antimicrobial activity; Antioxidant capacity; Bee pollen; DPPH; Palynological analysis
27) Feás, X., Pires, J., Iglesias, A., Estevinho, M.L.
Characterization of artisanal honey produced on the Northwest of Portugal by melissopalynological and physico-chemical data
(2010) Food and Chemical Toxicology, 48 (12), pp. 3462-3470.
Abstract
Honey has always been regarded as a food which is advantageous for one's health and as a product which has healing qualities. For this reason, is necessary to protect consumers from the fraudulent mislabeling of inferior honeys. The purpose of this study was to investigate some properties of artisanal honey samples (n= 45) collected from the Northwest of Portugal by using different honey analysis tests such as moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural (HMF), apparent sucrose, reducing sugars and diastase activity. 77.8% of the total exceeded the quality parameters and should be labeled as " virgin" (humidity ≤18% and HMF ≤ 25. mg/kg). The present study found a linear correlation (y= 0.551. x-0.089; R= 0.995) between the electrical conductivity of honeys and their ash content. All of the samples showed an Erica sp. pollen percentage ≥15%, and 42% of the total were monofloral Erica sp. In respect to coliforms and Salmonella's presence, all the honey's samples shown to be negative. The existence of sulphite-reducing Clostridia was low, and well below the established limit by MERCOSUR. Yeasts, moulds and aerobic mesophiles were detected in low amounts. © 2010 Elsevier Ltd.
Author Keywords
Honey; Melissopalynology; Physico-chemical properties; Quality parameters
28) Feás, X., Pires, J., Estevinho, M.L., Iglesias, A., de Araujo, J.P.P.
Palynological and physicochemical data characterisation of honeys produced in the Entre-Douro e Minho region of Portugal
(2010) International Journal of Food Science and Technology, 45 (6), pp. 1255-1262.
Abstract
Honey legislation has been addressed to establish the minimum marketing level of the product and the need for consumer protection through correct denominations. Research oriented toward assessment of floral origin and physicochemical properties may increase the commercial value of these products. The characteristics of thirty-one honeys produced in the Entre-Douro e Minho region in Portugal were studied. Pollen features and some physicochemical parameters (moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural contain, apparent sucrose, reducing sugars and diastase activity) were determined. The samples were found to meet international honey specifications. The present study found a linear regression between the ash content of honeys and their specific conductivity. Five samples are listed as Eucalyptus honey, one sample as Citrus honey, and twenty-five samples as multifloral honeys. Of the total, 87.1% exceeded the quality parameters and should be labelled as 'virgin' honey. © 2010 The Authors. Journal compilation © 2010 Institute of Food Science and Technology.
Author Keywords
Entre-Douro e Minho; Honey; Melissopalynology; Physicochemical analysis; Portugal
29) Hosseini, S.V., Abedian-Kenari, A., Rezaei, M., Nazari, R.M., Feás, X., Rabbani, M.
Influence of the in vivo addition of alpha-tocopheryl acetate with three lipid sources on the lipid oxidation and fatty acid composition of Beluga sturgeon, Huso huso, during frozen storage
(2010) Food Chemistry, 118 (2), pp. 341-348.
Abstract
This study was conducted to investigate the effect of dietary alpha-tocopheryl acetate (vitamin E) and oil sources on fish flesh quality characteristics of Huso huso during frozen storage. Practical-type diets containing 0 or 250 mg vitamin E kg-1 with three lipid sources, fish oil (FO), soybean oil (SO) and canola oil (CO), were fed to H. huso for 120 days. Fillet samples were analysed fresh or after storage at -18 ± 1 °C for 12 months. Replacement of FO by SO and CO in diets for H. huso significantly altered the fatty acid (FA) profile, which also influenced the FA composition during frozen storage. Dietary vitamin E had a significant effect on muscle vitamin E content and lipid oxidation during storage (P > 0.05). Oxidation was reduced for fish fed vitamin E and results showed that dietary vitamin E supplementation can slow down the level of lipid oxidation in H. huso muscles during frozen storage. © 2009.
Author Keywords
Beluga sturgeon; Canola oil; Fish oil; Frozen storage; Lipid oxidation; Soybean oil; Vitamin E
30) Feás, X., Ye, L., Hosseini, S.V., Fentea, C.A., Cepeda, A.
Molecularly imprinted polyallylamine hydrogels: Another reassessment
(2010) Polymer International, 59 (1), pp. 11-15.
Abstract
Researchers in the scientific community actively discuss the fact that polymer hydrogels synthesized by crosslinking polly(allylamine hydrochloride) (PAH) with epichlorohydrin (EPI) in the presence of D-glucose-6-phosphate monobarium salt do not show or show imprinting on the molecular level. In the work reported here, a polymer hydrogel was synthesized in the presence of flumequine (FQ) by crosslinking PAH with EPI in an aqueous system. The extent of FQ binding was assessed using liquid chromatography coupled with laser-induced fluorescence detection. A hydrogel-imprinting system was found to display FQ selectivity in binding assays (75.1 and 41.9%) compared with hydrogel formed in the absence of a template (41.6 and 20.4%). High-magnification scanning electron microscopy (SEM) images show that both of the hydrogels are highly ordered, exhibiting a 'honeycomb' pattern distribution. For the effect of the template molecule in the polymer structure (i.e. the imprinting effect in hydrogelmorphology), appreciable differences were observed for images obtained. The non-imprinted polymer had a uniform, smoothly shaped surface. By contrast, the hydrogel molecular imprinting polymer surface was more globular. This difference was likely caused by the structure of the target molecule. Binding experiment results correlate with surface morphology, as analysed using SEM, and indicate that imprinted hydrogels have recognizable cavities with an affinity for used FQ from the imprint. © 2009 Society of Chemical Industry.
Author Keywords
Flumequine; Hydrogels; Molecular imprinting; Polyallylamine; SEM (scanning electron microscopy)
31) Feás, X., Vázquez, B.I., Iglesias, A., Cantalapiedra, J., Fente, C.A., Cepeda, A.
Sensitive determination of decoquinate in milk by high-performance liquid chromatographic coupled to laser-induced fluorescence detection
(2010) Food Analytical Methods, 3 (3), pp. 138-143.
Abstract
A new and sensitive method based on high performance liquid chromatography with laser-induced fluorescence detection has been developed for the determination of decoquinate in milk. Laser source was obtained with a He-Cd laser using a continuous excitation wavelength at 325 nm. Decoquinate exhibits moderate fluorescence, but it is increased using Ca(NO 3) 2 in the mobile phase. The chromatographic separation was performed on a Luna C 18 5-mm reversed phase column, which solves the broadening of peaks and peak tailing compared with other columns tested. The mobile phase, delivered at 1 ml min -1, consisted of methanol-calcium nitrate (0.025 M)-acetonitrile (83/13/4 v/v/v). Decoquinate was successfully cleaned up from milk by solid-phase extraction using C 18 cartridges. The method was found to be linear between 0.16 and 16.33 ng ml -1. The results of recovery studies were found to be satisfactory; an average recovery rate of 88.7% was obtained. The LOQ of decoquinate in milk was 0.16 ng ml -1. The intraday relative standard deviation (RSD) was 4%, and interday assay gave an RSD of 4.4%. © 2009 Springer Science+Business Media, LLC.
Author Keywords
Decoquinate; Food Safety; Laser-Induced Fluorescence (LIF); Milk
32) Feás, X., Ye, L., Hosseini, S.V., Fente, C.A., Cepeda, A.
Development and validation of LC-MS/MS method for the determination of cyproheptadine in several pharmaceutical syrup formulations
(2009) Journal of Pharmaceutical and Biomedical Analysis, 50 (5), pp. 1044-1049.
Abstract
A rapid and sensitive liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method was developed and validated for the qualitative and quantitative assay of cyproheptadine (CP) in pharmaceutical samples. Diphenylpyraline hydrochloride (DPP) was used as an internal standard (IS). Two multiple reaction-monitoring (MRM) transitions for each analyte were observed: 288.1/96.1 and 288.1/191.2 for CP and 282.1/167.2 and 282.1/116.3 for DPP. The retention time of the drug was 7.29 min. The analytical method was successfully validated for linearity (1-100 ng/ml), intra-day precision, inter-day precision, and accuracy. The limit of detection (LOD) and limit of quantification (LOQ) were 0.86 and 0.98 ng/ml, respectively. The proposed method was applied to analyse the cyproheptadine content from seven different syrup formulations. © 2009 Elsevier B.V. All rights reserved.
Author Keywords
Cyproheptadine; Diphenylpyraline; Food residues; LC-MS/MS; Method validation; Pharmaceuticals
33) Feás, X., Fente, C.A., Cepeda, A.
Fast and sensitive new high performance liquid chromatography laser induced fluorescence (HPLC-LIF) method for quinine. Comparative study in soft drinks
(2009) Journal of Liquid Chromatography and Related Technologies, 32 (17), pp. 2600-2614.
Abstract
A simple, quick, and accurate new method for the determination of quinine (6'-methoxycinchonan-9-ol) in soft drinks is presented. The analysis is carried out using high performance liquid chromatography (HPLC), coupled laser induced fluorescence (LIF) that consisted of a 325nm He-Cd laser and a ZETALIF detector. The chromatographic separation was performed on a Phenomenex Synergi Fusion-Reversed Phase (RP) column and allows good peak shape and symmetry in less than 1.5min. A calibration curve ranging from 1 to 100ng/mL was shown to be linear with a correlation coefficient (R) of 0.9999. The limit of detection of quinine was 3.2 pg on the column. The method was applied to the analysis of several beverages (n=43) containing quinine, whose analysis required minimum pretreatment before direct injection, and can therefore be used for quality control in comparison to the classical methods. Data obtained from different commercial beverages containing quinine show no homogeneous concentration of this compound. This article describes, for the first time, the successful application of HPLC coupled LIF detection for quinine determination in common beverages.
Author Keywords
High performance liquid chromatography (HPLC); Laser-induced fluorescence (LIF); Quinine; Soft drinks
34) Pires, J., Estevinho, M.L., Feás, X., Cantalapiedra, J., Iglesias, A.
Pollen spectrum and physico-chemical attributes of heather (Erica sp.) honeys of north Portugal
(2009) Journal of the Science of Food and Agriculture, 89 (11), pp. 1862-1870.
Abstract
BACKGROUND: Honey legislation has been addressed to establish the minimum marketing level of the product and the need for consumer protection through correct denominations. Research oriented toward assessment of floral origin and physico-chemical properties may increase the commercial value of these products. The characteristics of 23 unifloral honeys of Erica sp., from Portugal, were studied. Pollen features and some physicochemical parameters (moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural content, apparent sucrose, reducing sugars and diastase activity) were determined. RESULTS: All honey samples can be classified as monofloral Erica sp., they gave a mean value of 56% of Erica pollen type. The families Fabaceae and Rosaceae provided the greatest number of pollen types with 8 and 4 pollen types each respectively. The second most important pollen type is Eucalyptus, present in 69.6% of the samples. All honey samples met the international physicochemical quality standards. The present study found a linear correlation (R = 0.996) between the ash content of honeys and their specific conductivity. CONCLUSION: All honey samples can be classified as monofloral Erica sp. Unifloral honeys are increasingly requested and appreciated, despite their higher prices. The samples were found to meet all major international honey specifications. © 2009 Society of Chemical Industry.
Author Keywords
Erica sp; Honey; Melissopalynology; Physico-chemical analysis
35) Álvarez, V., Feás, X., Barros-Velázquez, J., Aubourg, S.P.
Quality changes of farmed blackspot seabream (Pagellus bogaraveo) subjected to slaughtering and storage under flow ice and ozonised flow ice
(2009) International Journal of Food Science and Technology, 44 (8), pp. 1561-1571.
Abstract
Flow ice (FI) combined with ozone (OFI condition) was evaluated for slaughter and storage of farmed blackspot seabream (Pagellus bogaraveo) when compared with FI alone (FI condition). When processed in either OFI or FI conditions, this species exhibited slow biochemical and microbiological spoilage mechanisms when compared with other commercial fish species. The presence of ozone slowed down microbial development (1.00-3.53 and 1.60-4.04 log CFU g -1 for fish mesophile counts from OFI and FI conditions, respectively) and trimethylamine formation, so that fish kept under OFI condition was still acceptable at the end of the experiment (day 16), while its counterpart fish treated with FI was rejectable. In contrast, a small pro-oxidant effect could be assessed by means of the ozone presence; however, oxidation values (peroxide value and thiobarbituric acid index) reached at day 16 by individuals treated under OFI conditions (8.34 and 0.19, respectively) cannot be considered specially high. © 2009 Institute of Food Science and Technology.
Author Keywords
Blackspot seabream; Chilling storage; Farming; Ozone; Quality; Slaughtering
36) Feás, X., Ye, L., Regal, P., Fente, C.A., Hosseini, S.V., Cepeda, A.
Application of dummy molecularly imprinted solid-phase extraction in the analysis of cyproheptadine in bovine urine
(2009) Journal of Separation Science, 32 (10), pp. 1740-1747.
Abstract
Due to the difficulty of monitoring trace levels of cyproheptadine (CYP) residues in complicated biological matrices, specific adsorption materials for the preconcentration and clean-up of CYP are indispensable. In this work, CYP was extracted from urine using dummy molecularly imprinted SPE (DMISPE) to avoid leakage of the imprinting molecules during the desorption phase. For synthesis of DMISPE, azatadine (AZA) was employed as the dummy template, methacrylic acid (MAA) as the monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, 2,2′-azobis(2-methylpropionitrile) (AIBN) as the initiator, and dichloromethane as the porogen solvent. An LC-MS/MS method was used to analyze CYP. Two MRM (multiple reaction monitoring) transitions for each analyte were monitored using diphenylpyraline hydrochloride (DPP · HCl), which was used as an internal standard. The advantages of DMISPE include obtaining less complex chromatograms and reducing ion suppression in ESI. The process efficiencies for DMISPE and SPE were 80% and 12%, respectively. In addition, the demonstrated reusability of the DMISPE cartridges is an advantage compared with single-use SPE cartridges or immunoaffinity materials. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Author Keywords
Cyproheptadine; Dummy-molecularly imprinted solid-phase extraction; Food residues; LC-MS; MS
37) Feás Sánchez, X., Brašić, J.R., Fente, C.A., Cepeda, A.
Quinine potential toxicological implications: Analysis of tonic waters in Spain [La quinina y sus posibles implicaciones toxicológicas. Análisis de aguas tónkas en España]
(2009) Revista Espanola de Nutricion Comunitaria, 15 (2), pp. 97-102.
Abstract
Background: Quinine is an alkaloid naturally occurring in the crust of some trees of genus Rubiaceae, traditionally used for the treatment of malaria, seizures, and various infections. In this work we present results of samples tested in Spain, both of the concentration found and labelling, as well as related to the potential implications of quinine on public health. Methods: The content of quinine was analyzed in 11 samples of tonic waters in the Spanish market by liquid chromatography coupled through laser induced fluorescence detection. Results: The method used is characterized by its accuracy, speed and sensitivity. Quinine concentration in beverages is not homogeneous. The labelling does not indicate the quinine content. Conclusions: More specific regulation is needed as well as more information to consumers, especially for certain risk groups.
Author Keywords
Public health; Quinine; Soft drinks
38) Fente, C.A., Regal, P., Vázquez, B.I., Feás, X., Franco, C.M., Cepeda, A.
Development and validation of an LC-MS/MS confirmatory method for residue analysis of cyproheptadine in urine of food-producing animals
(2009) Journal of Agricultural and Food Chemistry, 57 (6), pp. 2595-2598.
Abstract
The possible off-label and illegal use of cyproheptadine (CYP) as an appetite stimulant for food-producing animals creates the need for methods capable of detecting it. A high-performance liquid chromatography tandem mass spectrometry method (LC-MS/MS) was developed to identify CYP in bovine urine, according to Commission Decision 2002/657/EC. Two multiple reaction monitoring (MRM) transitions for each analyte were monitored: 288.1/96.1 and 288.1/191.2 for CYP and 282.1/167.2 and 282.1/116.3 for diphenylpyraline hydrochloride (DPP), which was used as an internal standard. The solid phase extraction technique without a liquid-liquid step gives good results in urine samples from treated animals. The analytical method was successfully validated for linearity (0.15-10 ng/ml-), with intraday precision of 9.4%, interday precision of 20.4%, and accuracy of 96.7%. The decision limit (CCα) and detection capability (CCγ) were 0.48 and 0.82 ng/mL, respectively. © 2009 American Chemical Society.
Author Keywords
Bovine urine; Cyproheptadine; LC-MS/MS
39) Feás, X., Fente, C.A., Hosseini, S.V., Seijas, J.A., Vázquez, B.I., Franco, C.M., Cepeda, A.
Use of acrylic acid in the synthesis of molecularly imprinted polymers for the analysis of cyproheptadine
(2009) Materials Science and Engineering C, 29 (2), pp. 398-404.
Abstract
The synthesis and comparative characterization of molecularly imprinted polymers (MIPs) with cyproheptadine (CYP), using two different monomers, acrylic acid (AA) and methacrylic acid (MAA), are described. Polyacids (PA) [poly(methacrylic acid) (PMAA) and poly(acrylic acid) (PAA)] were obtained by the radical polymerization of MAA and AA, respectively, in dichloromethane as the porogen solvent-imprinted medium. The non-covalent imprinting process was performed via thermal decomposition of an azo-initiator at 60 °C, using ethylene glycol dimethacrylate as the cross-linker and 2,2′-azobis(2-methylpropionitrile) as the initiator. The selectivities of MIPs and NIPs particles were evaluated in binding experiments of the four synthesized polymeric materials (MIPaa, MIPmaa, NIPmaa and NIPaa) with CYP. The effects of monomers on: a) the surface morphology, b) the binding capacity and c) the swelling properties of imprinted and non-imprinted polymers were studied and are presented here. Polymer material morphology was assessed with scanning electron microscopy (SEM). This revealed differences in monomer function, depending on which one was employed, as well as differences in function when polymerization occurred in the presence of template or without it. Non-specific retention of the template to NIPs was higher for NIPs-PAA polymers than for NIPs-PMAA materials. In terms of specific binding (ΔQ = QMIP - QNIP), MIPmaa showed the greatest value (53.47%) in comparison with MIPaa (50.07%). Crown Copyright © 2008.
Author Keywords
Acrylic acid; Cyproheptadine; Methacrylic acid; Molecularly imprinted polymers (MIPs)
40) Feás, X., Seijas, J.A., Vázquez-Tato, M.P., Regal, P., Cepeda, A., Fente, C.
Syntheses of molecularly imprinted polymers: Molecular recognition of cyproheptadine using original print molecules and azatadine as dummy templates
(2009) Analytica Chimica Acta, 631 (2), pp. 237-244.
Abstract
The use of custom-made polymeric materials with high selectivities as target molecules in solid-phase extraction (SPE), known as molecularly imprinted solid-phase extraction (MISPE), is becoming an increasingly important sample preparation technique. However, the potential risk of leakage of the imprinting molecules during the desorption phase has limited application. The use of a mimicking template, called a dummy molecular imprinting polymer (DMIP), that bears the structure of a related molecule and acts as a putative imprinting molecule may provide a useful solution to this problem. In the current study, cyproheptadine (CPH) and azatadine (AZA) were used as templates in the development of an MIP and DMIP for acrylic acid and methacrylic acid monomers. Our results indicate that DMIPs have equal recognition of CPH, avoiding the problem of leakage of original template during the desorption phase relative to MIPs synthesized in presence of the print molecule CPH. Examination of the surface structure of the two polymer products by SEM shows appreciable differences in structural morphology and function of the monomers employed. These results are well supplemented by data obtained for swelling ratios and solvent uptake. Molecular modelling of CPH and AZA suggests that both substrates are similar in shape and volume. © 2008 Elsevier B.V. All rights reserved.
Author Keywords
Azatadine; Cyproheptadine; Dummy molecularly imprinted polymer
41) Feás, X., Fente, C.A., Hosseini, S.V., Cepeda, A.
New near ultraviolet laser-induced native fluorescence detection coupled to HPLC to analyse residues of oxolinic acid and flumequine: A comparison with conventional xenon flash lamp: Nuevo método de análisis de residuos de oxolínico y flumequina utilizando la detección de la fluorescencia nativa inducida por láser acoplada en el ultravioleta cercano acoplada al HPLC: Comparación con la lámpara de xenon convencional
(2009) CYTA - Journal of Food, 7 (1), pp. 15-21.
Abstract
A new high-performance liquid chromatography (HPLC) method is described for the determination of oxolinic acid and flumequine, with ultraviolet laser-induced fluorescence detection (UV-LIFD). Near-UV excitation at 325 nm was obtained by using an He/Cd laser. Data obtained using UV-LIFD and conventional fluorimetry (Xenon flash, λexc 325/ λem 365) are compared under the same chromatographic conditions, connecting in series both detectors, in terms of linearity, reproducibility and repeatability. The HPLC separation is carried out on a Synergi MAX-RP column with water–acetonitrile (2:1, v/v) adjusted at pH 2.5, with formic acid, as mobile phase and completed in less than 9 min. The detection limits of oxolinic acid and flumequine at a signal-to-noise ratio of 3 were 0.43 pg and 0.76 pg on column with UV-LIFD detection, making this method considerably more sensitive than traditional fluorescence detector (16.15 pg and 14.17 pg) having some obvious advantages. © 2009 Taylor & Francis Group, LLC.
Author Keywords
Flumequine; Laser induced fluorescence; Oxolinic
42) Moini, S., Tahergorabi, R., Hosseini, S.V., Rabbani, M., Tahergorabi, Z., Feás, X., Aflaki, F.
Effect of gamma radiation on the quality and shelf life of refrigerated rainbow trout (Oncorhynchus mykiss) fillets
(2009) Journal of Food Protection, 72 (7), pp. 1419-1426.
Abstract
The effect of gamma radiation (0, 1, 3, and 5 kGy) on the shelf life of farmed rainbow trout (Oncorhynchus mykiss) fillets that were treated with sodium acetate and vacuum packaged and subsequently stored under refrigeration was studied by measuring microbiological, chemical, and organoleptic changes. Radiation affected populations of bacteria, namely. H2S-producing bacteria and Enterobacteriaceae (P < 0.05). Initial total viable counts of the control samples were ca. 4.41 log CFU/g, whereas the respective counts in samples irradiated at 1,3, and 5 kGy were 3.08, 1.46, and ≤1 log CFU/g at day 1 of refrigerated storage. The maximum count of Enterobacteriaceae reached 2.29 and 1.45 log CFU/g at the end of storage for 1 and 3 kGy, respectively, but at a 5-kGy dose no growth of Enterobacteriaceae was observed. Of the biochemical indicators, thiobarbituric acid values for irradiated trout were higher than for nonirradiated fish (P < 0.05). Sensory evaluation (taste) showed a reasonable and good correlation with bacterial populations with storage time. The results revealed that radiation at a high dose (5 kGy) might induce lipid and protein oxidation, although the growth of microorganisms was inhibited. Therefore, radiation at a low dose (3 kGy) could be used to control the microbial and safety biochemical indices of O. mykiss for up to 4 weeks at refrigerator temperature without adverse effects on quality and acceptability. © International Association for Food Protection.
43) Hosseini, S.V., Behrooz, R.D., Esmaili-Sari, A., Bahramifar, N., Hosseini, S.M., Tahergorabi, R., Hosseini, S.F., Feás, X.
Contamination by organochlorine compounds in the edible tissue of four sturgeon species from the Caspian Sea (Iran)
(2008) Chemosphere, 73 (6), pp. 972-979.
Abstract
This study focused on accumulation of organochlorine compounds (OCs), including dichloro-diphenyl-trichloroethanes (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and polychlorinated biphenyls (PCBs) accumulation in the muscle of four sturgeon (Persian sturgeon, Acipenser persicus; Stellate sturgeon, Acipenser stellatus; Ship sturgeon, Acipenser nudiventris and Beluga sturgeon, Huso huso) from the southern Caspian Sea. The DDT group was prominent in all of the sturgeon muscle tested constituting almost half or more of the total organochlorine content. Contaminant concentration generally followed this order: DDTs > PCBs > HCHs > HCB. The OCs concentrations in Beluga sturgeon (H. huso) were the highest and over four times higher than in the next highest species (A. nudiventris). From an ecotoxicological point of view, the concentrations of OCs in experimental fishes do not reflect a comparatively clean and pollution-free environment; however, results from this study shown that the inflow of organic pollutants into the Caspian Sea has been reduced when compared with prior studies. Levels of measured OCs in sturgeon were relatively low, but the level of some OCs in some of the specimens tested exceeded the guidelines for food; therefore, the maximum allowable daily consumption rate for sturgeon from this watershed may be limited by DDTs and PCBs content for high risk populations. © 2008 Elsevier Ltd. All rights reserved.
Author Keywords
Caspian Sea; Iran; Organochlorine; Pollution; Sturgeon
44) Vázquez, B.I., Feás, X., Lolo, M., Fente, C.A., Franco, C.M., Cepeda, A.
Detection of synthetic corticosteroids in bovine urine by chemiluminescence high-performance liquid chromatography
(2005) Luminescence, 20 (3), pp. 197-204.
Abstract
The development of a black market of chemical cocktails for illegal growth promotion in food-producing animals includes substances that are potentially dangerous for human health, such as synthetic corticosteroids. The potential presence of these residues in food makes it necessary to develop rapid and sensitive analytical methodologies to detect such substances, preferably in live animals before they arrive at the market. A chemiluminescence (CL) detection method for the determination of four synthetic corticosteroids (prednisolone, betamethasone, dexamethasone and flumethasone) in bovine urine has been developed. The proposed system, which does not need any derivatization procedure, offers an easy method well suited for routine research. Urine samples were homogenized with methanol:water (50:50, v/v) and centrifuged. The upper layer was collected and Strata™ X cartridges were used for cleaning up. The purified residues were evaporated to dryness and then redissolved in the mobile phase. Analysis of the extracts was performed using high-performance liquid chromatography with chemiluminescence detection, employing luminol as the CL reagent. The recovery curves, obtained at four spiking levels (different for each corticosteroid), showed that recoveries of at least 70% could be obtained for urine. The chemiluminescence detection procedure afforded satisfactory results with respect to sensitivity and the LOD and LOQ, taken as the first point of the regression curve, ranged from 4 ppb to 65 ppb. The maximum mean RSD was below 13% and below 15% for intra- and inter-day assay, respectively, in all cases. Copyright © 2005 John Wiley & Sons, Ltd.
Author Keywords
Chemiluminiscence; Corticosteroids; HPLC; Urine
Influence of fining agents on the sensorial characteristics and volatile composition of mead
(2017) Journal of the Institute of Brewing, 123 (4), pp. 562-571.
Abstract
Mead, one of the oldest fermented drinks, is derived from the fermentation of diluted honey by yeasts. In the context of wine production, several procedures are applied to stabilize the beverage and to improve its organoleptic properties. This study aims to evaluate the impact of adding fining agents on the production of mead. In general, the best results were obtained for the samples containing just one fining agent instead of two combined. However, the best performance was obtained for the combined fining agents (bentonite + gelatine + egg albumin). Tannins decreased significantly the content of volatile compounds. On the other hand, silica appears to be the best fining agent, resulting in the lowest loss of volatile compounds. Thirty-six volatile compounds were determined by gas chromatograph–flame ionization detector and gas chromatography–mass spectrometry, including alcohols (42.5%), carbonyl compounds (40.4%), acetates (14.4%) and esters (1.8%). Eleven volatile compounds had odour activity values >1, representing those with a major impact on the aroma of mead. Significant differences (p < 0.05) were found in 10 volatile compounds independently to the type of treatment used and no differences (p > 0.05) were observed for remaining compounds. Copyright © 2017 The Institute of Brewing & Distilling. Copyright © 2017 The Institute of Brewing & Distilling
Author Keywords
fining agents; mead; odour activity values; sensorial analysis; volatile compounds
2) Feás, X., Pacheco, L., Iglesias, A., Estevinho, L.M.
Use of propolis in the sanitization of lettuce
(2014) International Journal of Molecular Sciences, 15 (7), pp. 12243-12257.
Abstract
The present study aimed to determine the effectiveness of propolis in reducing the microbial load in ready-to-eat (RTE) and fresh whole head (FWH) lettuces (Lactuca sativa L.) type Batavia. Two sanitizing solutions were employed: sodium hypochlorite (SH) and propolis (PS), during 15 and 30 min. Tap water (TW) was used as a control. Regarding the mean reduction on aerobic mesophiles, psychrotrophic and fecal coliforms, the SH and PS treatments showed the same pattern of variation. In all cases, PS was slightly more effective in the microbiological reduction in comparison with commercial SH. Reductions between two and three log cycles were obtained with PS on aerobic mesophiles and psychrotrophic counts. The information obtained in the present study can be used to evaluate the potential use of propolis as product for sanitizing other vegetables and for developing other food preservation technologies, with impact on human health. © 2014 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Lettuce; Microbiological safety; Propolis; Sanitization; Sodium hypochlorite
3) Vázquez-Tato, M.P., Mena-Menéndez, A., Feás, X., Seijas, J.A.
Novel microwave-assisted synthesis of the immunomodulator organotellurium compound ammonium trichloro(dioxoethylene-o,o')tellurate (AS101)
(2014) International Journal of Molecular Sciences, 15 (2), pp. 3287-3298.
Abstract
Ammonium trichloro[1,2-ethanediolato-O,O']-tellurate (AS101) is the most important synthetic Te compound from the standpoint of its biological activity. It is a potent immunomodulator with a variety of potential therapeutic applications and antitumoral action in several preclinical and clinical studies. An experimental design has been used to develop and optimize a novel microwave-assisted synthesis (MAOS) of the AS101. In comparison to the results observed in the literature, refluxing Te(IV) chloride and ethylene glycol in acetonitrile (Method A), or by refluxing Te(IV) chloride and ammonium chloride in ethylene glycol (Method B), it was found that the developed methods in the present work are an effective alternative, because although performance slightly decreases compared to conventional procedures (75% vs. 79% by Method A, and 45% vs. 51% by Method B), reaction times decreased from 4 h to 30 min and from 4 h to 10 min, by Methods A and B respectively. MAOS is proving to be of value in the rapid synthesis of compounds with new and improved biological activities, specially based on the benefit of its shorter reaction times. © 2014 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Ammonium trichloro[1,2-ethanediolato-O,O']-tellurate; Antitumoral; AS101; Microwave irradiation; Tellurium
4) Seijas, J.A., Crecente-Campo, J., Feás, X., Vázquez-Tato, M.P.
Microwave assisted synthesis, crystal structure and modelling of cytotoxic dehydroacetic acid enamine: A natural alkaloid from Fusarium incarnatum (HKI0504)
(2014) RSC Advances, 4 (33), pp. 17054-17059.
Abstract
A novel, fast and efficient method for the synthesis of (3E)-3-(1-aminoethylidene)-6-methyl-3,4-dihydro-2H-pyran-2,4-dione, a natural antiproliferative and cytotoxic product isolated from Fusarium incarnatum (HKI0504), was developed from dehydroacetic acid and urea under solvent-free microwave irradiation. The analysis of the co-crystal structure revealed an asymmetric unit formed by a pair of molecules. Each molecule is joined by two different hydrogen bonds to another two molecules, ordered as four-unit clusters linked by π-stacking, assembled in a brick like layered structure in a set of parallel walls. Besides, the preferred tautomer for crystal structure is the enamine form. This is corroborated by computational NBO analysis, outlining the contribution of enamine resonance and modelling the non-covalent interactions involved by means of Hirshfeld surfaces and G09 counterpoise calculations. © 2014 the Partner Organisations.
5) Pascoal, A., Rodrigues, S., Teixeira, A., Feás, X., Estevinho, L.M.
Biological activities of commercial bee pollens: Antimicrobial, antimutagenic, antioxidant and anti-inflammatory
(2014) Food and Chemical Toxicology, 63, pp. 233-239.
Abstract
Bee pollen is considered, since memorable times, a good source of nourishing substances and energy. The present study aimed to evaluate the biological activities of eight commercial bee pollens purchased from the market. The origin of sample A was not specified in the labeling; samples B, C, D and G were from Portugal and the remaining were from Spain. The sample E presented the highest value of phenolics (32.15. ±. 2.12. mg/g) and the H the lowest (18.55. ±. 095. mg/g). Sample C had the highest value of flavonoids (10.14. ±. 1.57. mg/g) and sample H the lowest (3.92. ±. 0.68. mg/g). All the samples exhibited antimicrobial activity, being Staphylococcus aureus the most sensitive and Candida glabrata the most resistant of the microorganisms studied. All the samples exhibited antimutagenic activity, even though some samples were more effective in decreasing the number of gene conversion colonies and mutant colonies. Regarding the antioxidant activity, assessed using two methods, the more effective was sample B. The anti-inflammatory activity, assessed using the hyaluronidase enzyme, was highest in samples B and D. Pearson's correlation coefficients between polyphenols, flavonoids, antioxidant activity and antimicrobial activity were computed. It was also performed a discriminant analysis. © 2013 Elsevier Ltd.
Author Keywords
Antimicrobial activity; Antimutagenicity; Antioxidant activity; Bee pollen; Bioactive compounds; Inflammation
6) Pascoal, A., Feás, X., Dias, T., Dias, L.G., Estevinho, L.M.
The Role of Honey and Propolis in the Treatment of Infected Wounds
(2014) Microbiology for Surgical Infections: Diagnosis, Prognosis and Treatment, pp. 221-234.
Abstract
Honey as a natural, unprocessed and easily digested food is a valuable nutritive product for children, athletes and convalescents. It has been used in ethno-medicine since the prehistoric times, and recently in the treatment of burns, healing wounds, chronic wounds, gastrointestinal disorders, asthma, skin ulcers, cancer, oncology, and as an antioxidant and antimicrobial agent. Propolis is prepared by bees of the Apis mellifera species, using resinous substances collected from various plants, and has been reported to possess pharmacological properties, such as antibiotic, anti-neoplastic, anti-inflammatory, anti-diarrheatic, antimicrobial, antiviral, antioxidant, hepatoprotective, cariostatic, antitumoral, anti-ulcerus, immunostimulator, antineurodegenerative, antituberculosis and anti-HIV-1 activity. The biological activity of these products is mainly attributed to phenolic compounds, such as flavonoids. In this context, the topical application of beehive products, particularly honey and propolis, has great potential in the treatment of several injuries and diseases, since it would improve patients' outcome without undesirable side effects. This chapter aims to present information from published studies regarding the beneficial effects of those products on a range of medical conditions and infected wounds. © 2014 Elsevier Inc. All rights reserved.
Author Keywords
Antimicrobial activities; Honey; Infected wounds and healing; Phenolic compounds; Propolis
7) Iglesias, A., Pascoal, A., Choupina, A.B., Carvalho, C.A., Feás, X., Estevinho, L.M.
Developments in the fermentation process and quality improvement strategies for mead production
(2014) Molecules, 19 (8), pp. 12577-12590.
Abstract
Mead is a traditional alcoholic drink derived from the fermentation of diluted honey in the presence of appropriate yeast. Its modern production, in general terms, involves the addition of nutrients to initial diluted honey, pasteurization, yeast inoculation, fermentation and removal of impurities. Undesirable events along the process have been reported; among them, we highlight: delayed or arrested fermentations, modified and unpleasant sensory and quality parameters of the final product. These problems have been linked to the inability of yeasts to accomplish their role in extreme growth conditions. Emphasis has also been placed on the long fermentation times required, ranging from weeks to months, particularly when traditional procedures are applied and when the honey concentration is low. A series of alterations to the must and technological changes have been proposed in order to optimize the mead production process. In this context, this review examines the evidence that aims to improve meads' quality and make the production process easier and more efficient, by clarifying the source of unexpected events, describing the implementation of different fermentative microorganisms and using new methodologies. © 2014 by the authors.
Author Keywords
Fermentation progress; Fermentative microorganisms; Honey; Mead production; Quality procedures
8) Hosseini, S.V., Hamzeh, A., Moslemi, M., Lashkan, A.B., Iglesias, A., Feás, X.
Effect of delayed icing on biogenic amines formation and bacterial contribution of iced common carp (cyprinus carpio)
(2013) Molecules, 18 (12), pp. 15464-15473.
Abstract
The variation of six biogenic amines (BAs) and total viable count (TVC) in common carp (Cyprinus carpio) stored in ice with 0, 4 and 8 h delay before icing was evaluated in a period of 4 days. Delayed icing led to significant (p < 0.05) increases in TVC throughout the period of storage and showed a good correlation with BAs content. The obtained data showed that putrescine and cadaverine were predominant in all samples and it was indicated that they could be proper indicators to determine the carp quality. Spermidine and spermine increased slightly toward the end of storage and the levels of dangerous BAs (histamine and tyramine) were under the limit over the period. As a result, it is indicated that delaying time affects on formation of BAs and the effect in samples with 8 h delay was significantly (p < 0.05) more than those with 0 and 4 h delay. © 2013 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Biogenic amines; Carp; Delayed icing; Fish; Storage
9) Feás, X., Iglesias, A., Rodrigues, S., Estevinho, L.M.
Effect of Erica sp. honey against microorganisms of clinical importance: Study of the factors underlying this biological activity
(2013) Molecules, 18 (4), pp. 4233-4246.
Abstract
This study aimed to determine the factors (phenolic compounds, flavonoids, sugars or H2O2) that contribute the most to the antimicrobial activity of heather honey samples against four yeasts and four bacteria with medical importance. To discard the effect of H2O 2 in the antimicrobial activity, catalase was added. To evaluate the osmotic pressure's effect, artificial honey was also used. Phenolic compounds and flavonoids were determined and Pearson's correlation analysis was performed to assess whether these correlated with antimicrobial activity. The amount of phenolic compounds ranged from 630.89 ± 5.21 GAE kg-1 to 718.92 ± 4.41 GAE kg-1, while the flavonoids varied between 450.72 ± 5.67 CAE kg-1 and 673.98 ± 4.33 CAE kg -1. For the bacteria, the minimum inhibitory concentration (MIC) of the honey without catalase ranged from 1.01 ± 0.50% to 10.00 ± 4.72% and was between 2.00 ± 0.94% and 13.27 ± 5.23% for honey with catalase. Concerning the yeasts, the MICs was between 13.16 ± 4.08% and 20.00 ± 5.09% for honey without catalase and between 14.95 ± 4.16% and 25.67 ± 5.50% for honey with catalase. The elucidation of the antimicrobial factors and action mechanisms is essential for the correct use of honey in therapeutic applications. © 2013 by the authors.
Author Keywords
Antibacterial properties; Antifungal properties; Heather honey; Hydrogen peroxide; Polyphenols; Sugars
10) Feás, X., Estevinho, L.M., Salinero, C., Vela, P., Sainz, M.J., Vázquez-Tato, M.P., Seijas, J.A.
Triacylglyceride, antioxidant and antimicrobial features of virgin camellia oleifera, C. reticulata and C. sasanqua oils
(2013) Molecules, 18 (4), pp. 4573-4587.
Abstract
Virgin oils obtained from seeds of Camellia oleifera (CO), Camellia reticulata (CR) and Camellia sasanqua (CS) were studied for their triacylglyceride composition, antioxidant and antimicrobial activities. Levels of fatty acids determined by 1H-nuclear magnetic resonance analysis were similar to those reported for olive oils (82.30%-84.47%; 5.69%-7.78%; 0.26%-0.41% and 8.04%-11.2%, for oleic, linoleic, linolenic and saturated acids, respectively). The CR oil showed the best antioxidant potential in the three in vitro models tested. With regard to EC50 values (μg/mL), the order in DPPH radical-scavenging was CR (33.48) < CO (35.20) < CS (54.87). Effectiveness in reducing power was CR (2.81) < CO (3.09) < CS (5.32). IC50 for LPO inhibition were 0.37, 0.52 and 0.75 μg/mL for CR, CO and CS, respectively. All the oils showed antimicrobial activity, and exhibited different selectivity and MICs for each microorganism tested (E. coli, B. cereus and C. albicans). B. cereus was the less sensitive species (MIC: 52.083 ± 18.042 for CO; 41.667 ± 18.042 for CR; 104.167 ± 36.084 for CS mg/mL) and the E. coli was the most sensitive to camellia oil's effect. The standard gentamicin presented higher MIC for E. coli (4.2) than the CR (MIC= 2.6) and CO (MIC = 3.9) oils. © 2013 by the authors.
Author Keywords
Antimicrobial activity; Antioxidant potential; Camellia; Oil; Triacylglyceride
11) Estevinho, M., Vázquez-Tato, M., Seijas, J., Feás, X.
Palynological, physicochemical, and microbiological attributes of organic lavender (Lavandula stoechas) honey from Portugal
(2013) Acta Alimentaria, 42 (1), pp. 36-44.
Abstract
At the present time, the quality, integrity, sanitation, and nutritional value of honeys receive attention on an international level due to the increasing content of chemicals in the aforementioned matrix. The present study aims to characterize organic honey (n=73) from Northeast Portugal, with respect to floral nectar origin, physicochemical parameters, microbial safety, and commercial quality. All organic honey samples can be classified as monofloral lavender (Lavandula stoechas L.), exceed in quality the international physicochemical standards, and show low microbiological counts (yeast, moulds, and aerobic mesophiles), with negative results in respect to faecal coliforms, Salmonella, and sulphite-reducing clostridia. Correlating the palynological, physicochemical, and microbiological results is necessary in order to check the authenticity, quality, and sanitation of honey.
Author Keywords
honey; microbiological analysis; organic; physicochemical attributes
12) Salinero, C., Feás, X., Mansilla, J.P., Seijas, J.A., Vázquez-Tato, M.P., Vela, P., Sainz, M.J.
1H-nuclear magnetic resonance analysis of the triacylglyceride composition of cold-pressed oil from Camellia japonica.
(2012) Molecules (Basel, Switzerland), 17 (6), pp. 6716-6727.
Abstract
Camellia japonica (CJ) has oil-rich seeds, but the study of these oils has received little attention and has mainly focused only on their health properties. In the present work the relative composition of the fatty acid (FA) components of the triglycerides in cold-pressed oil from CJ is studied by 1H-NMR. The results obtained were: 75.75%, 6.0%, 0.17% and 18.67%, for oleic, linoleic, linolenic and saturated FA respectively. Levels of C 18 unsaturated FA found in CJ oil were similar to those reported for olive oils. We also checked the possibility of using 13C-NMR spectroscopy; however, the results confirmed the drawback of 13C over 1H-NMR for the study of FA components of CJ triglycerides due to its low gyromagnetic ratio and its very low natural abundance.
13) Feas, X., Vazquez-Tato, M.P., Estevinho, L., Seijas, J.A., Iglesias, A.
Organic bee pollen: Botanical origin, nutritional value, bioactive compounds, antioxidant activity and microbiological quality
(2012) Molecules, 17 (7), pp. 8359-8377.
Abstract
Organic bee pollen (BP, n = 22) harvested from the Douro International Natural Park (DINP, Portugal) was studied. Nine botanical families were found in the mixture of the samples. The water activity and pH ranged 0.21-0.37 and 4.3-5.2, respectively. The BP analyses averaged 67.7% carbohydrates, 21.8% crude protein, 5.2% crude fat and 2.9% ash. The energy ranged from 396.4 to 411.1 kcal/100 g. The principal fatty acid found was linolenic, followed by linoleic acid, palmitic acid and oleic acid. The phenolic and flavonoid contents varied from 12.9 to 19.8 mg of gallic acid equivalents/g of extract and from 4.5 to 7.1 mg of catechin equivalents/g of extract, respectively. The scavenger activity and β-carotene bleaching assays values (EC 50) were 3.0 μ 0.7 mg/mL and 4.6 mg/mL μ 0.9 mg/mL, respectively. E. coli, sulphite-reducing Clostridia, Salmonella and S. aureus were not found. Since there are studies indicating appreciable differences among BPs from different regions, the full characterization of BP from diverse origins still appears to be a sound research priority in order to obtain reliable data about this beehive product. © 2012 by the authors.
Author Keywords
Antioxidant capacity; Bee pollen; Bioactive compound; Fatty acids; Microbiological safety; Organic food
14) Iglesias, A., Feás, X., Rodrigues, S., Seijas, J.A., Vázquez-Tato, M.P., Dias, L.G., Estevinho, L.M.
Comprehensive study of honey with protected denomination of origin and contribution to the enhancement of legal specifications
(2012) Molecules, 17 (7), pp. 8561-8577.
Abstract
In this study the characterization of a total of 60 honey samples with Protected Denomination of Origin (PDO) collected over three harvests (2009-2011, inclusive), from the Northeast of Portugal was carried out based on the presence of pollen, physicochemical and microbiological characteristics. All samples were found to meet the European Legislation, but some didn′t meet the requirements of the PDO specifications. Concerning the floral origin of honey, our results showed the prevalence of rosemary (Lavandula pedunculata) pollen. The microbiological quality of all the analyzed samples was satisfactory, since fecal coliforms, sulfite-reducing clostridia and Salmonella were absent, and molds and yeasts were detected in low counts. Significant differences between the results were studied using one-way analysis of variance (ANOVA), followed by Tukey′s HSD test. The samples were submitted to discriminant function analysis, in order to determine which variables differentiate between two or more naturally occurring groups (Forward Stepwise Analysis). The variables selected were in this order: diastase activity, pH, reducing sugars, free acidity and HMF. The pollen spectrum has perfect discriminatory power. This is the first study inwhich a honey with PDO was tested, in order to assess its compliance with the PDO book of specifications. © 2012 by the authors.
Author Keywords
Honey; Microbiological; Palynological; Physicochemical; Protected Denomination of Origin
15) Salinero, C., Feás, X., Pedro Mansilla, J., Seijas, J.A., Pilar Vázquez-Tato, M., Vela, P., Sainz, M.J.
1H-nuclear magnetic resonance analysis of the triacylglyceride composition of cold-pressed oil from Camellia japonica
(2012) Molecules, 17 (6), pp. 6716-6727.
Abstract
Camellia japonica (CJ) has oil-rich seeds, but the study of these oils has received little attention and has mainly focused only on their health properties. In the present work the relative composition of the fatty acid (FA) components of the triglycerides in cold-pressed oil from CJ is studied by 1H-NMR. The results obtained were: 75.75%, 6.0%, 0.17% and 18.67%, for oleic, linoleic, linolenic and saturated FA respectively. Levels of C 18 unsaturated FA found in CJ oil were similar to those reported for olive oils. We also checked the possibility of using 13C-NMR spectroscopy; however, the results confirmed the drawback of 13C over 1H-NMR for the study of FA components of CJ triglycerides due to its low gyromagnetic ratio and its very low natural abundance. © 2012 by the authors.
Author Keywords
13C-NMR; 1H-NMR; Camellia japonica; Nuclear magnetic resonance; Oil; Triacylglycerides
16) Silva, J.C., Rodrigues, S., Feás, X., Estevinho, L.M.
Antimicrobial activity, phenolic profile and role in the inflammation of propolis
(2012) Food and Chemical Toxicology, 50 (5), pp. 1790-1795.
Abstract
Nowadays a great amount of information regarding chemical and biological aspects of bee products is available in the literature, but few data on its therapeutic uses are found. The aim of this study was to evaluate the phenolic profile, the in vitro antimicrobial activity and effect in the hyaluronidase enzyme (widely related with the inflammation process) of propolis harvested in Portugal. The efficacy of three extracts (hydro-alcoholic, methanolic and aqueous) was also compared. It was chosen the hydro-alcoholic extract, because this was the most effective for extracting phenolic compounds. The antimicrobial activity was accessed in Gram-positive and Gram-negative bacteria and yeasts, isolated from different biological fluids and the results were then compared with the obtained for reference microorganisms. The propolis from Bragança was the one that possessed the highest polyphenols' content. The sample from Beja showed the less significant inhibition of the hyaluronidase enzyme. Concerning the antimicrobial activity, Candida albicans was the most resistant and Staphylococcus aureus the most sensitive. The reference microorganisms were more sensitive than the ones isolated from biological fluids. © 2012 Elsevier Ltd.
Author Keywords
Antimicrobial activity; Hyaluronidase; Inflammation; Phenolic compounds; Propolis
17) Estevinho, M.L., Feás, X., Seijas, J.A., Vázquez-Tato, M.P.
Physicochemical and pollen analysis of Local honeys from the Lima Valley (Portugal)
(2012) Electronic Journal of Environmental, Agricultural and Food Chemistry, 11 (3), pp. 214-221.
Abstract
An evaluation was done on the physicochemical quality of nineteen (n=19) Apis mellifera honeys produced in the Lima Valley, Portugal. The rural landscape of the Lima Valley is valuable in social, environmental and economic terms and its conservation and preservation are essential. The evaluated physicochemical characteristics were: moisture, ash, electrical conductivity, pH, hydroxymethylfurfural (HMF), free acidity, apparent sucrose, reducing sugars and diastase activity. All honey samples met the International physicochemical quality standards. A short study of pollen source was done by acetolisis method. The families Fabaceae and Rosaceae were found with 6 and 2 pollen types each respectively. The most important pollen source is Erica, moreover two samples are listed as Erica monofloral honey.
Author Keywords
Erica; Honey; Lima valley; Physicochemical characteristics; Pollen analysis; Portugal; Quality
18) Estevinho, L.M., Rodrigues, S., Pereira, A.P., Feás, X.
Portuguese bee pollen: Palynological study, nutritional and microbiological evaluation
(2012) International Journal of Food Science and Technology, 47 (2), pp. 429-435.
Abstract
Bee pollen is one of the richest and purest natural foods, used in the folk medicine, clinical practices, and food and pharmaceutical industries. This work aims to characterise, for the first time in Portugal, the palynological origin, nutritional value and microbiological safety of this beehive product. It identified ten botanical families, and the more frequent were Boraginaceae and Ericaceae. We have evaluated the water content, a w, pH, reducing sugars, ash, carbohydrate, proteins, lipids, fatty acids and energy. The microorganisms studied were the aerobic mesophiles, moulds and yeasts, faecal coliforms, Escherichia coli, Staphylococcus aureus, Salmonella and sulphite-reducing clostridia. The studied pollens are nutritionally well balanced, and contain high levels of moisture, proteins, fat, energy, ash, carbohydrates, reducing sugars, essential n-3 fatty acids and good ratios of polyunsaturated fatty acids (PUFA)/saturated fatty acids. In fact, the PUFA represent 66% of the total fatty acids. The samples had good microbiological quality, as none of the samples had toxigenic species. © 2011 Institute of Food Science and Technology.
Author Keywords
Bee pollen; Fatty acids; Microbiological safety; Nutrients
19) Estevinho, L.M., Feás, X., Seijas, J.A., Pilar Vázquez-Tato, M.
Organic honey from Trás-Os-Montes region (Portugal): Chemical, palynological, microbiological and bioactive compounds characterization
(2012) Food and Chemical Toxicology, 50 (2), pp. 258-264.
Abstract
At the present time, the quality, integrity, sanitation and nutritional value of honeys receive attention on an international level due to the increasing content of chemicals in the aforementioned matrix. This work was conducted to evaluate the quality of 75 organic honey samples from the Trás-Os-Montes region (Portugal). Mean values obtained for physico-chemical parameters were: pH 3.7; 15.6% moisture; 0.26mS/cm electrical conductivity; 0.25% ash; 1.1mg/kg HMF; 15.3 Gothe diastase activity; 40.3meq/kg free acidity; 67.8% invert sugars and 2.7% apparent sucrose. All honey samples can be classified as monofloral Erica sp., as showed by pollen features. The amounts of phenols and flavonoids in the samples were also determined. In respect to sanitary quality (fecal coliforms) and safety (sulfite-reducing clostridia and Salmonella), all organic honey samples were negative. Furthermore, yeast and molds were detected in low counts, with mean values obtained of 5.5cfu/g and the value of total aerobic mesophiles obtained from honeys was established in 1.3×10 2cfu/g±7.5×10 1cfu/g. The levels of flavonoids had a stronger impact on both mesophiles (p=0.0004) and molds (p=0.0138) than the sucrose concentration (p=0.001 and 0.0278; respectively). The results reported in this study should be introduced in the organic honey label, and may help beekeepers, the industry, researchers and consumers better understand honey properties. © 2011 Elsevier Ltd.
Author Keywords
Bioactive compounds; Erica sp.; Honey; Microbiological analysis; Organic; Physico-chemical analysis
20) Nogueira, C., Iglesias, A., Feás, X., Estevinho, L.M.
Commercial bee pollen with different geographical origins: A comprehensive approach
(2012) International Journal of Molecular Sciences, 13 (9), pp. 11173-11187.
Abstract
Since the primordial of humanity, pollen has been considered a good source of nutrients and energy. Its promising healing properties have also been referred to. The present study aimed to characterize, for the first time, eight commercial pollens from Portugal and Spain available on the market studying the legislation on labeling, pollinic origin, physicochemical and microbiological analyses and identification of yeasts. Eleven botanical families were found amongst the samples. The most abundant family and the most dominant pollen was Cistaceae. The moisture content, ash, aw, pH, reducing sugars, carbohydrates, proteins, lipids and energy were analyzed and the specific parameters were within the specifications required by some countries with legislation regarding these parameters. Microbiologically commercial pollen showed acceptable safety for the commercial quality and hygiene. All samples showed negative results for toxigenic species. The microorganisms studied were aerobic mesophiles, yeasts and moulds, coliforms, Escherichia coli, Staphylococcus aureus, Salmonella and sulfite-reducing Clostridium. During the work, six yeasts species were isolated from pollen, with Rhodotorula mucilaginosa being the most abundant, as it was present in four samples. © 2012 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Bee pollen; Labeling rules; Microbiological characterization; Physicochemical characterization; Pollinic analysis
21) Feás, X., Estevinho, M.L.
A Survey of the in vitro antifungal activity of heather (Erica Sp.) Organic honey
(2011) Journal of Medicinal Food, 14 (10), pp. 1284-1288.
Abstract
Monofloral heather (Erica sp.) honey samples (n=89), harvested in Portugal according to European organic beekeeping rules, were analyzed to test their antifungal effect against Candida albicans, Candida krusei, and Cryptococcus neoformans. A synthetic honey solution was also tested to determine antifungal activity attributable to sugars. The specific growth rate (μ) values showed that growth of all the yeasts was reduced in the presence of honey. The honey concentration (% wt/vol) that inhibited 10% of the yeast growth (X min) was 13.5% for C. albicans, 20.5% for C. krusei, and 17.1% for C. neoformans. The respective concentrations of heather honey and synthetic honey in the C. krusei culture medium above 60% (wt/vol) that inhibited 90% of the yeast growth (X max) and X min, respectively, were established, whereas C. albicans and C. neoformans were more resistant because X max values were not reached over the range tested (10-60%, wt/vol). Heather honey might be tapped as a natural resource to look for new medicines for the treatment of mycotic infections. Further studies are now required to demonstrate if this antifungal activity has any clinical application. © 2011 Mary Ann Liebert, Inc.
Author Keywords
antifungal effects; Candida albicans; Candida krusei; Cryptococcus neoformans; Erica species; honey
22) Estevinho, M.L., Afonso, S.E.T., Feás, X.
Antifungal effect of lavender honey against Candida albicans, Candida krusei and Cryptococcus neoformans
(2011) Journal of Food Science and Technology, 48 (5), pp. 640-643.
Abstract
Monofloral lavender honey samples (n=30), were analyzed to test antifungal effect against Candida albicans, Candida krusei, and Cryptococcus neoformans. The specific growth rates (μ) showed that all the yeast growths were reduced in the presence of honey. The honey concentration (% w/v) that inhibited 10% of the yeasts growth (Xmin) ranged from 31.0% (C. albicans), 16.8% (C. krusei) and 23.0% (C. neoformans). A synthetic honey solution was also tested to determine antifungal activity attributable to sugars. The presence of synthetic honey in the C. krusei culture medium at concentrations above 58.0% (w/v) was established as Xmin, while C. albicans and C. neoformans were more resistant, since Xmin values were not reached over the ranged tested (10-60%, w/v). What the data suggests is that the component in the lavender honey responsible for the observed antifungal in vitro properties is not sugar based. Honey might be tapped as a natural resource to look for new medicines for the treatment of mycotic infections. This could be very useful, onsidering the increasing resistance of antifungals. It should be noticed that this is the first study concerning the effect of lavender honey on the growth of pathogenic yeasts. © 2011 Association of Food Scientists & Technologists (India).
Author Keywords
Antifungal; Candida albicans; Candida krusei; Cryptococcus neoformans; Honey; Lavender
23) Cerqueira, J.O.L., Feás, X., Iglesias, A., Pacheco, L.F., Araújo, J.P.P.
Morphological traits in Portuguese Bordaleira de Entre Douro e Minho sheep: Divergence of the breed
(2011) Animal Production Science, 51 (7), pp. 635-641.
Abstract
Production of the autochthonous Portuguese sheep breed Bordaleira de Entre Douro e Minho (BEDM) is directly associated with the concept of sustainable agriculture. This concept focuses on the adaptation of animal populations to adverse environmental conditions, high biological efficiency and traditional management. Native BEDM sheep can be divided into the following two types on the basis of their geographic location in Portugal and how they are managed: the Vrzea, which is found mainly in the lower Entre Douro e Minho region, and the Mountain type, which traditionally prefers common areas. In the present work, we analysed records of liveweight, 15 body measurements and eight indexes of the BEDM sheep, to explore the ability to distinguish different characteristics between BEDM sheep populations. The records that were obtained and analysed by principal component analysis for 412 BEDM sheep (68 males and 344 females) included the following: heights at withers (HW), at back (HB), at rump (HR) and at chest (HC); lengths of trunk (LT), of rump (LR), of head (LH) and of perineum (LP); widths of head (WH), of chest (WC), of biiliac (WBIIL) and of biischiatic (WBIIS); perimeters of the shin (PS), thorax (PT), and abdomen (PA); and finally indexes such as cephalic index (CI), thoracic index (TI), pelvic index (PI), body index (BI), relative chest depth index (RDCI), lateral corporal index (LCI), relative shin thickness index (RTSI) and dactylthoracic index (DTI). The Vrzea BEDM was morphologically superior to the Mountain variety, with this superiority more evident in females. Height measurements, especially HW in adult females, provided an excellent measurement reference for biometrical breed studies. Functional index values confirmed the BEDM Mountain variety's appropriateness for mountainous regions. Relationships among body measurements suggested that the breed standard needed to be updated. The research presented here was used by the Portuguese Ministery to split BEDM into two new breeds; the traditional variety called Vrzea now represents the new BEDM breed, whereas the Mountain variety represents the new Churra do Minho breed. © CSIRO 2011.
Author Keywords
Churra do Minho breed; Portugal
24) Gomes, T., Feás, X., Iglesias, A., Estevinho, L.M.
Study of organic honey from the northeast of Portugal
(2011) Molecules, 16 (7), pp. 5374-5386.
Abstract
Concerns about traces of numerous toxic substances and authenticity have prompted consumer demand for honey that is certified as organic, based on strict ecological, natural principles and traceability. The present study aims to characterize organic honey samples (n = 73) from Northeast Portugal, with respect to floral nectar origin, physicochemical parameters and microbial safety. The phenols and flavonoids contents, often referred to as responsible for honey's bioactive properties, were also assessed. All organic honey samples were classified as monofloral lavender (Lavandula sp.), exceeded in quality the international physicochemical standards and showed low microbiological counts (yeast, moulds and aerobic mesophiles), with negative results in respect to fecal coliforms, Salmonella and sulphite-reducing Clostridium spp. Correlation of the palynological, physicochemical and microbiological results is necessary to check the authenticity, quality and sanitation of honey. Although not required by international legislation, results of those assessments provide a complete outlook and elucidation of the organic honey's properties, which could promote its valorisation. © 2011 by the authors; licensee MDPI, Basel, Switzerland.
Author Keywords
Honey; Lavender; Microbiology; Organic foods; Phenolic compounds; Physicochemical properties
25) Iglesias, A., De Jesus, C., Cantalapiedra, J.J., Sanchez, L., Feas, X.
Cryopreservation of semen of celta breed boars
(2011) Indian Veterinary Journal, 88 (7), pp. 28-29.
Abstract
The data of fresh semen characteristics, the possible effects of freezing on sperm viability, and seminal variables due to changes in annual cycle were studied in the autochthonous Celta breed (NW Spain). In fresh semen, the following parameters were computed: ejaculate volume (202±26.6 ml), sperm motility (82.1±1.2 %), sperm concentration (401±35.1x106 sperm/ml), normal acrosomes (86.8±6.3 %), distal cytoplasmic droplets (12.1±6.1 %) and abnormal sperm cells (26.1±9.8 %). The ejaculate volume was affected by the month, maximum temperature, minimum temperature, minimum relative humidity and the interaction between maximum temperature and minimum relative humidity. Freezing semen had a significant effect on spermatic characteristics, even though viability (57.64±10.1 %), motility (73.3±3.2 %) remained at acceptable levels.
26) Morais, M., Moreira, L., Feás, X., Estevinho, L.M.
Honeybee-collected pollen from five Portuguese Natural Parks: Palynological origin, phenolic content, antioxidant properties and antimicrobial activity
(2011) Food and Chemical Toxicology, 49 (5), pp. 1096-1101.
Abstract
The aim of this study was to determine the palynological origin, phenolic content, antioxidant and antimicrobial properties of pollen from five Portuguese Natural-Parks [Parque Nacional Peneda Gerês (PNPG); Parque Natural do Montesinho (PNM); Parque Natural do Alvão (PNA); Parque Natural da Serra da Estrela (PNSE) and Parque Natural do Douro Internacional (PNDI)]. Eight families were found in the mixture of bee pollen: Rosaceae, Cistaceae, Boraginaceae, Asteraceae, Fagaceae, Ericaeae, Myrtaceae and Fabaceae. The phenolic compounds content, determined by the Folin-Ciocalteu method, varied between 10.5 and 16.8mg of gallic acid equivalents/g of extract (mg GAE/g) found in bee pollen from PNM and PNDI, respectively. The free radical scavenging measured showed the highest effective extract - PNM with EC50 2.16, followed by PND with 2.24mg/mL. In the β-carotene bleaching assay the same behaviour as in the DPPH method was verified. We also verified that the presence of pollen differentially affected the growth of bacteria Gram-positive, Gram-negative and yeasts under study, depending this on the microorganism and the pollen used. This is an important study since, as far we know, it is the first time that Portuguese bee pollen from Natural Parks was studied, and their characterization can increase their economic value. © 2011.
Author Keywords
β-Carotene bleaching assay; Antimicrobial activity; Antioxidant capacity; Bee pollen; DPPH; Palynological analysis
27) Feás, X., Pires, J., Iglesias, A., Estevinho, M.L.
Characterization of artisanal honey produced on the Northwest of Portugal by melissopalynological and physico-chemical data
(2010) Food and Chemical Toxicology, 48 (12), pp. 3462-3470.
Abstract
Honey has always been regarded as a food which is advantageous for one's health and as a product which has healing qualities. For this reason, is necessary to protect consumers from the fraudulent mislabeling of inferior honeys. The purpose of this study was to investigate some properties of artisanal honey samples (n= 45) collected from the Northwest of Portugal by using different honey analysis tests such as moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural (HMF), apparent sucrose, reducing sugars and diastase activity. 77.8% of the total exceeded the quality parameters and should be labeled as " virgin" (humidity ≤18% and HMF ≤ 25. mg/kg). The present study found a linear correlation (y= 0.551. x-0.089; R= 0.995) between the electrical conductivity of honeys and their ash content. All of the samples showed an Erica sp. pollen percentage ≥15%, and 42% of the total were monofloral Erica sp. In respect to coliforms and Salmonella's presence, all the honey's samples shown to be negative. The existence of sulphite-reducing Clostridia was low, and well below the established limit by MERCOSUR. Yeasts, moulds and aerobic mesophiles were detected in low amounts. © 2010 Elsevier Ltd.
Author Keywords
Honey; Melissopalynology; Physico-chemical properties; Quality parameters
28) Feás, X., Pires, J., Estevinho, M.L., Iglesias, A., de Araujo, J.P.P.
Palynological and physicochemical data characterisation of honeys produced in the Entre-Douro e Minho region of Portugal
(2010) International Journal of Food Science and Technology, 45 (6), pp. 1255-1262.
Abstract
Honey legislation has been addressed to establish the minimum marketing level of the product and the need for consumer protection through correct denominations. Research oriented toward assessment of floral origin and physicochemical properties may increase the commercial value of these products. The characteristics of thirty-one honeys produced in the Entre-Douro e Minho region in Portugal were studied. Pollen features and some physicochemical parameters (moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural contain, apparent sucrose, reducing sugars and diastase activity) were determined. The samples were found to meet international honey specifications. The present study found a linear regression between the ash content of honeys and their specific conductivity. Five samples are listed as Eucalyptus honey, one sample as Citrus honey, and twenty-five samples as multifloral honeys. Of the total, 87.1% exceeded the quality parameters and should be labelled as 'virgin' honey. © 2010 The Authors. Journal compilation © 2010 Institute of Food Science and Technology.
Author Keywords
Entre-Douro e Minho; Honey; Melissopalynology; Physicochemical analysis; Portugal
29) Hosseini, S.V., Abedian-Kenari, A., Rezaei, M., Nazari, R.M., Feás, X., Rabbani, M.
Influence of the in vivo addition of alpha-tocopheryl acetate with three lipid sources on the lipid oxidation and fatty acid composition of Beluga sturgeon, Huso huso, during frozen storage
(2010) Food Chemistry, 118 (2), pp. 341-348.
Abstract
This study was conducted to investigate the effect of dietary alpha-tocopheryl acetate (vitamin E) and oil sources on fish flesh quality characteristics of Huso huso during frozen storage. Practical-type diets containing 0 or 250 mg vitamin E kg-1 with three lipid sources, fish oil (FO), soybean oil (SO) and canola oil (CO), were fed to H. huso for 120 days. Fillet samples were analysed fresh or after storage at -18 ± 1 °C for 12 months. Replacement of FO by SO and CO in diets for H. huso significantly altered the fatty acid (FA) profile, which also influenced the FA composition during frozen storage. Dietary vitamin E had a significant effect on muscle vitamin E content and lipid oxidation during storage (P > 0.05). Oxidation was reduced for fish fed vitamin E and results showed that dietary vitamin E supplementation can slow down the level of lipid oxidation in H. huso muscles during frozen storage. © 2009.
Author Keywords
Beluga sturgeon; Canola oil; Fish oil; Frozen storage; Lipid oxidation; Soybean oil; Vitamin E
30) Feás, X., Ye, L., Hosseini, S.V., Fentea, C.A., Cepeda, A.
Molecularly imprinted polyallylamine hydrogels: Another reassessment
(2010) Polymer International, 59 (1), pp. 11-15.
Abstract
Researchers in the scientific community actively discuss the fact that polymer hydrogels synthesized by crosslinking polly(allylamine hydrochloride) (PAH) with epichlorohydrin (EPI) in the presence of D-glucose-6-phosphate monobarium salt do not show or show imprinting on the molecular level. In the work reported here, a polymer hydrogel was synthesized in the presence of flumequine (FQ) by crosslinking PAH with EPI in an aqueous system. The extent of FQ binding was assessed using liquid chromatography coupled with laser-induced fluorescence detection. A hydrogel-imprinting system was found to display FQ selectivity in binding assays (75.1 and 41.9%) compared with hydrogel formed in the absence of a template (41.6 and 20.4%). High-magnification scanning electron microscopy (SEM) images show that both of the hydrogels are highly ordered, exhibiting a 'honeycomb' pattern distribution. For the effect of the template molecule in the polymer structure (i.e. the imprinting effect in hydrogelmorphology), appreciable differences were observed for images obtained. The non-imprinted polymer had a uniform, smoothly shaped surface. By contrast, the hydrogel molecular imprinting polymer surface was more globular. This difference was likely caused by the structure of the target molecule. Binding experiment results correlate with surface morphology, as analysed using SEM, and indicate that imprinted hydrogels have recognizable cavities with an affinity for used FQ from the imprint. © 2009 Society of Chemical Industry.
Author Keywords
Flumequine; Hydrogels; Molecular imprinting; Polyallylamine; SEM (scanning electron microscopy)
31) Feás, X., Vázquez, B.I., Iglesias, A., Cantalapiedra, J., Fente, C.A., Cepeda, A.
Sensitive determination of decoquinate in milk by high-performance liquid chromatographic coupled to laser-induced fluorescence detection
(2010) Food Analytical Methods, 3 (3), pp. 138-143.
Abstract
A new and sensitive method based on high performance liquid chromatography with laser-induced fluorescence detection has been developed for the determination of decoquinate in milk. Laser source was obtained with a He-Cd laser using a continuous excitation wavelength at 325 nm. Decoquinate exhibits moderate fluorescence, but it is increased using Ca(NO 3) 2 in the mobile phase. The chromatographic separation was performed on a Luna C 18 5-mm reversed phase column, which solves the broadening of peaks and peak tailing compared with other columns tested. The mobile phase, delivered at 1 ml min -1, consisted of methanol-calcium nitrate (0.025 M)-acetonitrile (83/13/4 v/v/v). Decoquinate was successfully cleaned up from milk by solid-phase extraction using C 18 cartridges. The method was found to be linear between 0.16 and 16.33 ng ml -1. The results of recovery studies were found to be satisfactory; an average recovery rate of 88.7% was obtained. The LOQ of decoquinate in milk was 0.16 ng ml -1. The intraday relative standard deviation (RSD) was 4%, and interday assay gave an RSD of 4.4%. © 2009 Springer Science+Business Media, LLC.
Author Keywords
Decoquinate; Food Safety; Laser-Induced Fluorescence (LIF); Milk
32) Feás, X., Ye, L., Hosseini, S.V., Fente, C.A., Cepeda, A.
Development and validation of LC-MS/MS method for the determination of cyproheptadine in several pharmaceutical syrup formulations
(2009) Journal of Pharmaceutical and Biomedical Analysis, 50 (5), pp. 1044-1049.
Abstract
A rapid and sensitive liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method was developed and validated for the qualitative and quantitative assay of cyproheptadine (CP) in pharmaceutical samples. Diphenylpyraline hydrochloride (DPP) was used as an internal standard (IS). Two multiple reaction-monitoring (MRM) transitions for each analyte were observed: 288.1/96.1 and 288.1/191.2 for CP and 282.1/167.2 and 282.1/116.3 for DPP. The retention time of the drug was 7.29 min. The analytical method was successfully validated for linearity (1-100 ng/ml), intra-day precision, inter-day precision, and accuracy. The limit of detection (LOD) and limit of quantification (LOQ) were 0.86 and 0.98 ng/ml, respectively. The proposed method was applied to analyse the cyproheptadine content from seven different syrup formulations. © 2009 Elsevier B.V. All rights reserved.
Author Keywords
Cyproheptadine; Diphenylpyraline; Food residues; LC-MS/MS; Method validation; Pharmaceuticals
33) Feás, X., Fente, C.A., Cepeda, A.
Fast and sensitive new high performance liquid chromatography laser induced fluorescence (HPLC-LIF) method for quinine. Comparative study in soft drinks
(2009) Journal of Liquid Chromatography and Related Technologies, 32 (17), pp. 2600-2614.
Abstract
A simple, quick, and accurate new method for the determination of quinine (6'-methoxycinchonan-9-ol) in soft drinks is presented. The analysis is carried out using high performance liquid chromatography (HPLC), coupled laser induced fluorescence (LIF) that consisted of a 325nm He-Cd laser and a ZETALIF detector. The chromatographic separation was performed on a Phenomenex Synergi Fusion-Reversed Phase (RP) column and allows good peak shape and symmetry in less than 1.5min. A calibration curve ranging from 1 to 100ng/mL was shown to be linear with a correlation coefficient (R) of 0.9999. The limit of detection of quinine was 3.2 pg on the column. The method was applied to the analysis of several beverages (n=43) containing quinine, whose analysis required minimum pretreatment before direct injection, and can therefore be used for quality control in comparison to the classical methods. Data obtained from different commercial beverages containing quinine show no homogeneous concentration of this compound. This article describes, for the first time, the successful application of HPLC coupled LIF detection for quinine determination in common beverages.
Author Keywords
High performance liquid chromatography (HPLC); Laser-induced fluorescence (LIF); Quinine; Soft drinks
34) Pires, J., Estevinho, M.L., Feás, X., Cantalapiedra, J., Iglesias, A.
Pollen spectrum and physico-chemical attributes of heather (Erica sp.) honeys of north Portugal
(2009) Journal of the Science of Food and Agriculture, 89 (11), pp. 1862-1870.
Abstract
BACKGROUND: Honey legislation has been addressed to establish the minimum marketing level of the product and the need for consumer protection through correct denominations. Research oriented toward assessment of floral origin and physico-chemical properties may increase the commercial value of these products. The characteristics of 23 unifloral honeys of Erica sp., from Portugal, were studied. Pollen features and some physicochemical parameters (moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural content, apparent sucrose, reducing sugars and diastase activity) were determined. RESULTS: All honey samples can be classified as monofloral Erica sp., they gave a mean value of 56% of Erica pollen type. The families Fabaceae and Rosaceae provided the greatest number of pollen types with 8 and 4 pollen types each respectively. The second most important pollen type is Eucalyptus, present in 69.6% of the samples. All honey samples met the international physicochemical quality standards. The present study found a linear correlation (R = 0.996) between the ash content of honeys and their specific conductivity. CONCLUSION: All honey samples can be classified as monofloral Erica sp. Unifloral honeys are increasingly requested and appreciated, despite their higher prices. The samples were found to meet all major international honey specifications. © 2009 Society of Chemical Industry.
Author Keywords
Erica sp; Honey; Melissopalynology; Physico-chemical analysis
35) Álvarez, V., Feás, X., Barros-Velázquez, J., Aubourg, S.P.
Quality changes of farmed blackspot seabream (Pagellus bogaraveo) subjected to slaughtering and storage under flow ice and ozonised flow ice
(2009) International Journal of Food Science and Technology, 44 (8), pp. 1561-1571.
Abstract
Flow ice (FI) combined with ozone (OFI condition) was evaluated for slaughter and storage of farmed blackspot seabream (Pagellus bogaraveo) when compared with FI alone (FI condition). When processed in either OFI or FI conditions, this species exhibited slow biochemical and microbiological spoilage mechanisms when compared with other commercial fish species. The presence of ozone slowed down microbial development (1.00-3.53 and 1.60-4.04 log CFU g -1 for fish mesophile counts from OFI and FI conditions, respectively) and trimethylamine formation, so that fish kept under OFI condition was still acceptable at the end of the experiment (day 16), while its counterpart fish treated with FI was rejectable. In contrast, a small pro-oxidant effect could be assessed by means of the ozone presence; however, oxidation values (peroxide value and thiobarbituric acid index) reached at day 16 by individuals treated under OFI conditions (8.34 and 0.19, respectively) cannot be considered specially high. © 2009 Institute of Food Science and Technology.
Author Keywords
Blackspot seabream; Chilling storage; Farming; Ozone; Quality; Slaughtering
36) Feás, X., Ye, L., Regal, P., Fente, C.A., Hosseini, S.V., Cepeda, A.
Application of dummy molecularly imprinted solid-phase extraction in the analysis of cyproheptadine in bovine urine
(2009) Journal of Separation Science, 32 (10), pp. 1740-1747.
Abstract
Due to the difficulty of monitoring trace levels of cyproheptadine (CYP) residues in complicated biological matrices, specific adsorption materials for the preconcentration and clean-up of CYP are indispensable. In this work, CYP was extracted from urine using dummy molecularly imprinted SPE (DMISPE) to avoid leakage of the imprinting molecules during the desorption phase. For synthesis of DMISPE, azatadine (AZA) was employed as the dummy template, methacrylic acid (MAA) as the monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, 2,2′-azobis(2-methylpropionitrile) (AIBN) as the initiator, and dichloromethane as the porogen solvent. An LC-MS/MS method was used to analyze CYP. Two MRM (multiple reaction monitoring) transitions for each analyte were monitored using diphenylpyraline hydrochloride (DPP · HCl), which was used as an internal standard. The advantages of DMISPE include obtaining less complex chromatograms and reducing ion suppression in ESI. The process efficiencies for DMISPE and SPE were 80% and 12%, respectively. In addition, the demonstrated reusability of the DMISPE cartridges is an advantage compared with single-use SPE cartridges or immunoaffinity materials. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Author Keywords
Cyproheptadine; Dummy-molecularly imprinted solid-phase extraction; Food residues; LC-MS; MS
37) Feás Sánchez, X., Brašić, J.R., Fente, C.A., Cepeda, A.
Quinine potential toxicological implications: Analysis of tonic waters in Spain [La quinina y sus posibles implicaciones toxicológicas. Análisis de aguas tónkas en España]
(2009) Revista Espanola de Nutricion Comunitaria, 15 (2), pp. 97-102.
Abstract
Background: Quinine is an alkaloid naturally occurring in the crust of some trees of genus Rubiaceae, traditionally used for the treatment of malaria, seizures, and various infections. In this work we present results of samples tested in Spain, both of the concentration found and labelling, as well as related to the potential implications of quinine on public health. Methods: The content of quinine was analyzed in 11 samples of tonic waters in the Spanish market by liquid chromatography coupled through laser induced fluorescence detection. Results: The method used is characterized by its accuracy, speed and sensitivity. Quinine concentration in beverages is not homogeneous. The labelling does not indicate the quinine content. Conclusions: More specific regulation is needed as well as more information to consumers, especially for certain risk groups.
Author Keywords
Public health; Quinine; Soft drinks
38) Fente, C.A., Regal, P., Vázquez, B.I., Feás, X., Franco, C.M., Cepeda, A.
Development and validation of an LC-MS/MS confirmatory method for residue analysis of cyproheptadine in urine of food-producing animals
(2009) Journal of Agricultural and Food Chemistry, 57 (6), pp. 2595-2598.
Abstract
The possible off-label and illegal use of cyproheptadine (CYP) as an appetite stimulant for food-producing animals creates the need for methods capable of detecting it. A high-performance liquid chromatography tandem mass spectrometry method (LC-MS/MS) was developed to identify CYP in bovine urine, according to Commission Decision 2002/657/EC. Two multiple reaction monitoring (MRM) transitions for each analyte were monitored: 288.1/96.1 and 288.1/191.2 for CYP and 282.1/167.2 and 282.1/116.3 for diphenylpyraline hydrochloride (DPP), which was used as an internal standard. The solid phase extraction technique without a liquid-liquid step gives good results in urine samples from treated animals. The analytical method was successfully validated for linearity (0.15-10 ng/ml-), with intraday precision of 9.4%, interday precision of 20.4%, and accuracy of 96.7%. The decision limit (CCα) and detection capability (CCγ) were 0.48 and 0.82 ng/mL, respectively. © 2009 American Chemical Society.
Author Keywords
Bovine urine; Cyproheptadine; LC-MS/MS
39) Feás, X., Fente, C.A., Hosseini, S.V., Seijas, J.A., Vázquez, B.I., Franco, C.M., Cepeda, A.
Use of acrylic acid in the synthesis of molecularly imprinted polymers for the analysis of cyproheptadine
(2009) Materials Science and Engineering C, 29 (2), pp. 398-404.
Abstract
The synthesis and comparative characterization of molecularly imprinted polymers (MIPs) with cyproheptadine (CYP), using two different monomers, acrylic acid (AA) and methacrylic acid (MAA), are described. Polyacids (PA) [poly(methacrylic acid) (PMAA) and poly(acrylic acid) (PAA)] were obtained by the radical polymerization of MAA and AA, respectively, in dichloromethane as the porogen solvent-imprinted medium. The non-covalent imprinting process was performed via thermal decomposition of an azo-initiator at 60 °C, using ethylene glycol dimethacrylate as the cross-linker and 2,2′-azobis(2-methylpropionitrile) as the initiator. The selectivities of MIPs and NIPs particles were evaluated in binding experiments of the four synthesized polymeric materials (MIPaa, MIPmaa, NIPmaa and NIPaa) with CYP. The effects of monomers on: a) the surface morphology, b) the binding capacity and c) the swelling properties of imprinted and non-imprinted polymers were studied and are presented here. Polymer material morphology was assessed with scanning electron microscopy (SEM). This revealed differences in monomer function, depending on which one was employed, as well as differences in function when polymerization occurred in the presence of template or without it. Non-specific retention of the template to NIPs was higher for NIPs-PAA polymers than for NIPs-PMAA materials. In terms of specific binding (ΔQ = QMIP - QNIP), MIPmaa showed the greatest value (53.47%) in comparison with MIPaa (50.07%). Crown Copyright © 2008.
Author Keywords
Acrylic acid; Cyproheptadine; Methacrylic acid; Molecularly imprinted polymers (MIPs)
40) Feás, X., Seijas, J.A., Vázquez-Tato, M.P., Regal, P., Cepeda, A., Fente, C.
Syntheses of molecularly imprinted polymers: Molecular recognition of cyproheptadine using original print molecules and azatadine as dummy templates
(2009) Analytica Chimica Acta, 631 (2), pp. 237-244.
Abstract
The use of custom-made polymeric materials with high selectivities as target molecules in solid-phase extraction (SPE), known as molecularly imprinted solid-phase extraction (MISPE), is becoming an increasingly important sample preparation technique. However, the potential risk of leakage of the imprinting molecules during the desorption phase has limited application. The use of a mimicking template, called a dummy molecular imprinting polymer (DMIP), that bears the structure of a related molecule and acts as a putative imprinting molecule may provide a useful solution to this problem. In the current study, cyproheptadine (CPH) and azatadine (AZA) were used as templates in the development of an MIP and DMIP for acrylic acid and methacrylic acid monomers. Our results indicate that DMIPs have equal recognition of CPH, avoiding the problem of leakage of original template during the desorption phase relative to MIPs synthesized in presence of the print molecule CPH. Examination of the surface structure of the two polymer products by SEM shows appreciable differences in structural morphology and function of the monomers employed. These results are well supplemented by data obtained for swelling ratios and solvent uptake. Molecular modelling of CPH and AZA suggests that both substrates are similar in shape and volume. © 2008 Elsevier B.V. All rights reserved.
Author Keywords
Azatadine; Cyproheptadine; Dummy molecularly imprinted polymer
41) Feás, X., Fente, C.A., Hosseini, S.V., Cepeda, A.
New near ultraviolet laser-induced native fluorescence detection coupled to HPLC to analyse residues of oxolinic acid and flumequine: A comparison with conventional xenon flash lamp: Nuevo método de análisis de residuos de oxolínico y flumequina utilizando la detección de la fluorescencia nativa inducida por láser acoplada en el ultravioleta cercano acoplada al HPLC: Comparación con la lámpara de xenon convencional
(2009) CYTA - Journal of Food, 7 (1), pp. 15-21.
Abstract
A new high-performance liquid chromatography (HPLC) method is described for the determination of oxolinic acid and flumequine, with ultraviolet laser-induced fluorescence detection (UV-LIFD). Near-UV excitation at 325 nm was obtained by using an He/Cd laser. Data obtained using UV-LIFD and conventional fluorimetry (Xenon flash, λexc 325/ λem 365) are compared under the same chromatographic conditions, connecting in series both detectors, in terms of linearity, reproducibility and repeatability. The HPLC separation is carried out on a Synergi MAX-RP column with water–acetonitrile (2:1, v/v) adjusted at pH 2.5, with formic acid, as mobile phase and completed in less than 9 min. The detection limits of oxolinic acid and flumequine at a signal-to-noise ratio of 3 were 0.43 pg and 0.76 pg on column with UV-LIFD detection, making this method considerably more sensitive than traditional fluorescence detector (16.15 pg and 14.17 pg) having some obvious advantages. © 2009 Taylor & Francis Group, LLC.
Author Keywords
Flumequine; Laser induced fluorescence; Oxolinic
42) Moini, S., Tahergorabi, R., Hosseini, S.V., Rabbani, M., Tahergorabi, Z., Feás, X., Aflaki, F.
Effect of gamma radiation on the quality and shelf life of refrigerated rainbow trout (Oncorhynchus mykiss) fillets
(2009) Journal of Food Protection, 72 (7), pp. 1419-1426.
Abstract
The effect of gamma radiation (0, 1, 3, and 5 kGy) on the shelf life of farmed rainbow trout (Oncorhynchus mykiss) fillets that were treated with sodium acetate and vacuum packaged and subsequently stored under refrigeration was studied by measuring microbiological, chemical, and organoleptic changes. Radiation affected populations of bacteria, namely. H2S-producing bacteria and Enterobacteriaceae (P < 0.05). Initial total viable counts of the control samples were ca. 4.41 log CFU/g, whereas the respective counts in samples irradiated at 1,3, and 5 kGy were 3.08, 1.46, and ≤1 log CFU/g at day 1 of refrigerated storage. The maximum count of Enterobacteriaceae reached 2.29 and 1.45 log CFU/g at the end of storage for 1 and 3 kGy, respectively, but at a 5-kGy dose no growth of Enterobacteriaceae was observed. Of the biochemical indicators, thiobarbituric acid values for irradiated trout were higher than for nonirradiated fish (P < 0.05). Sensory evaluation (taste) showed a reasonable and good correlation with bacterial populations with storage time. The results revealed that radiation at a high dose (5 kGy) might induce lipid and protein oxidation, although the growth of microorganisms was inhibited. Therefore, radiation at a low dose (3 kGy) could be used to control the microbial and safety biochemical indices of O. mykiss for up to 4 weeks at refrigerator temperature without adverse effects on quality and acceptability. © International Association for Food Protection.
43) Hosseini, S.V., Behrooz, R.D., Esmaili-Sari, A., Bahramifar, N., Hosseini, S.M., Tahergorabi, R., Hosseini, S.F., Feás, X.
Contamination by organochlorine compounds in the edible tissue of four sturgeon species from the Caspian Sea (Iran)
(2008) Chemosphere, 73 (6), pp. 972-979.
Abstract
This study focused on accumulation of organochlorine compounds (OCs), including dichloro-diphenyl-trichloroethanes (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and polychlorinated biphenyls (PCBs) accumulation in the muscle of four sturgeon (Persian sturgeon, Acipenser persicus; Stellate sturgeon, Acipenser stellatus; Ship sturgeon, Acipenser nudiventris and Beluga sturgeon, Huso huso) from the southern Caspian Sea. The DDT group was prominent in all of the sturgeon muscle tested constituting almost half or more of the total organochlorine content. Contaminant concentration generally followed this order: DDTs > PCBs > HCHs > HCB. The OCs concentrations in Beluga sturgeon (H. huso) were the highest and over four times higher than in the next highest species (A. nudiventris). From an ecotoxicological point of view, the concentrations of OCs in experimental fishes do not reflect a comparatively clean and pollution-free environment; however, results from this study shown that the inflow of organic pollutants into the Caspian Sea has been reduced when compared with prior studies. Levels of measured OCs in sturgeon were relatively low, but the level of some OCs in some of the specimens tested exceeded the guidelines for food; therefore, the maximum allowable daily consumption rate for sturgeon from this watershed may be limited by DDTs and PCBs content for high risk populations. © 2008 Elsevier Ltd. All rights reserved.
Author Keywords
Caspian Sea; Iran; Organochlorine; Pollution; Sturgeon
44) Vázquez, B.I., Feás, X., Lolo, M., Fente, C.A., Franco, C.M., Cepeda, A.
Detection of synthetic corticosteroids in bovine urine by chemiluminescence high-performance liquid chromatography
(2005) Luminescence, 20 (3), pp. 197-204.
Abstract
The development of a black market of chemical cocktails for illegal growth promotion in food-producing animals includes substances that are potentially dangerous for human health, such as synthetic corticosteroids. The potential presence of these residues in food makes it necessary to develop rapid and sensitive analytical methodologies to detect such substances, preferably in live animals before they arrive at the market. A chemiluminescence (CL) detection method for the determination of four synthetic corticosteroids (prednisolone, betamethasone, dexamethasone and flumethasone) in bovine urine has been developed. The proposed system, which does not need any derivatization procedure, offers an easy method well suited for routine research. Urine samples were homogenized with methanol:water (50:50, v/v) and centrifuged. The upper layer was collected and Strata™ X cartridges were used for cleaning up. The purified residues were evaporated to dryness and then redissolved in the mobile phase. Analysis of the extracts was performed using high-performance liquid chromatography with chemiluminescence detection, employing luminol as the CL reagent. The recovery curves, obtained at four spiking levels (different for each corticosteroid), showed that recoveries of at least 70% could be obtained for urine. The chemiluminescence detection procedure afforded satisfactory results with respect to sensitivity and the LOD and LOQ, taken as the first point of the regression curve, ranged from 4 ppb to 65 ppb. The maximum mean RSD was below 13% and below 15% for intra- and inter-day assay, respectively, in all cases. Copyright © 2005 John Wiley & Sons, Ltd.
Author Keywords
Chemiluminiscence; Corticosteroids; HPLC; Urine
