Browsing by Author "Sanches-Silva, A."
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- Active Food Packaging with Antioxidant Properties: Incorporation of Plant Extracts in Polymeric Matrices to Extend Food Shelf-lifePublication . Sanches-Silva, A.; Carvalho-Costa, D.; Reis, A.R.; Albuquerque, T.G.; Castilho, M.C.; Ramos, F.; Machado, A.V.; Costa, H.S.Antioxidants (AOs) play an important role in biological processes because they prevent the effect of reactive oxygen species, protecting against cancer, inflammatory processes, cardiovascular diseases and aging, and consequently the degenerative diseases associated with it. In foods, AOs prevent oxidation which causes their deterioration and limits their shelf lives. Synthetic antioxidants are very effective against lipid oxidation, however some of them have been associated to toxic effects, which have increased the interest of food industry for natural substances also effective against this phenomenon. One of the main roles of food packaging is to retard the natural processes that lead to food deterioration. AOs can be incorporated into food packaging and be released by a controlled mechanism of diffusion. The use of AOs in food packaging may delay both lipid oxidation and protein denaturation. Packaging designed to foster desirable interactions with its content has been called active packaging. This innovative food packaging concept can extend the shelf life of food through the release of AOs by a controlled mechanism of diffusion from the packaging to the food surface and dissolution in it or in the inner atmosphere of the product or by the scavenging of free radicals. The release mechanism provides a continuous replenishment of AOs to foods and therefore, can reduce the direct addition of chemicals to the food. Rosemary (Rosmarinus officinalis L.) is a widely consumed aromatic herb that belongs to the Lamiaceae family. It is a xeromorphic species that grows spontaneously on sand, cliffs and stony places near the sea in many parts of the world. The fresh and dried leaves are frequently used as a food preservative and in traditional Mediterranean cuisine as a flavouring agent, being used with meat, fish, baked potatoes and sauces. Due to the influence of different factors such as growing conditions on the content of natural antioxidants, different rosemary commercial brands were compared. Antioxidant activity (radical 2,2-diphenyl-1-picrylhidrazyl (DPPH) scavenging activity), total phenolics and total flavonoids were evaluated. Moreover, their content on natural antioxidants, carnosic acid, carnosol and rosmarinic acid was quantified by an Ultra High Performance Liquid Chromatographic method coupled with a diode array detector (UHPLC-DAD) which has been validated in our laboratory. Finally, carotenoids and vitamin E were also evaluated following another UHPLC-DAD optimized in our laboratory. Rosemary extract has been approved as food additive (Directives 2010/67/EU and 2010/69/EU). In line with this, rosemary was also used to obtain a rosemary extract with high antioxidant activity. In fact, different solvents were tested in order to evaluate which originated higher antioxidant activity. Those with higher antioxidant activity and individual antioxidants content were used to produce active food packaging. Due to environmental motivation there is an increasing interest in the use of biodegradable/compostable packaging and/or edible materials. This tendency increases when materials come from industrial waste or renewable resources. Although rosemary extract has already been used in non-biodegradable matrices, to our knowledge, it is the first time that it has been used to produce biodegradable active packaging. Therefore, different polymeric matrices were evaluated, biodegradable and non-biodegradable. Migration tests were carried with food simulants at standard conditions. Promising results were found until now, and the new packaging material will also be tested in contact with foods in order to check their capacity to inhibit lipid oxidation, allowing to preserve the quality of foodstuffs and to increase their shelf-life. Our research group of the Department of Food and Nutrition from the National Institute of Health Dr. Ricardo Jorge (INSA) has great experience in the development of analytical methods for the determination of bioactive compounds (namely antioxidants) in foodstuffs and food byproducts as well as in food-packaging interactions and mathematical modelling of migration. Moreover it has a large number of peer-review publications in this field as well as national and international collaborations with other researcher groups that work in the same or complementary fields. Some of the groups that work in close collaboration with ours include the research group of Prof. Jaime López Cervantes from the Technological Institute of Sonora (México) and the research groups of Prof. Perfecto Paseiro and Prof. José Manuel Cruz from the Universities of Santiago de Compostela and Vigo, respectively. In the future, this research group intends to extend the research to other aromatic herbs and food by-products in order to search for new and interesting extracts that can be used to produce antioxidant active food packaging, with special interest in biodegradable matrices. The final aim is to be able to extend food shelf life reducing the direct additives of antioxidants to foods with positive health implications, at long term, for the consumers.
- Active Packaging Produced by Extrusion with Shrimp Waste: Migration of Astaxanthin into Food SimulantsPublication . Sanches-Silva, A.; Ribeiro, T.; Albuquerque, T.G.; Paseiro, P.; Sendón, R.; Bernaldo de Quirós, A.; López-Cervantes, J.; Sánchez-Machado, D.; Soto Valdez, H.; Angulo, I.; Pardo Aurrekoetxea, G.; Costa, H.S.Introduction: Astaxanthin (3,3’-dihydroxy-β-β´-carotene-4-4´-dione), a potent antioxidant, is one of the major carotenoids in crustaceans. In the frame of the project ‘Preparation of active packaging with antioxidant and antimicrobial activity based on astaxanthin and chitosan’, a methodology for the incorporation of compounds obtained from shrimp waste in plastic matrices was developed to produce an active packaging with antioxidant properties. The aim of the present work was to develop and optimize a method to determine astaxanthin by ultra-high pressure liquid chromatography in fermented shrimp waste. Moreover, the method was also applied to determine the migration of astaxanthin from plastic films containing different amounts of shrimp waste to food simulants. Material and Methods: The method was optimized to determine astaxanthin by ultra-high pressure liquid chromatography (UHPLC) with diode array detection (DAD). The chromatographic separation was achieved using a vanguard pre-column (UPLCÒ BEH, 1.7 µm particle size) and a column (UPLCÒ BEH, 2.1 x 50 mm, 1.7 µm particle size) at 20 °C. The mobile phase was a gradient of A (dichloromethane/methanol with ammonium acetate/acetonitrile 5:20:75 (v/v)) and B (ultrapure water) with a flow rate of 0.5 mL/min. The optimized UPLC method allowed an excellent resolution of astaxanthin. The method was also evaluated in what concerns to validation parameters such as linearity, precision, limit of detection, limit of quantification and recovery. Low density polyethylene plastic films produced by extrusion with different amounts of the lipid fraction of shrimp waste were prepared and tested regarding migration into fatty food stimulants (isooctane and ethanol 95%, v/v). Results and conclusion: The proposed method to determine astaxanthin in shrimp waste is simple and has a low detection level (0.054 μg/mL). The concentration of astaxanthin found in the lipid fraction of fermented shrimp waste was 453.8 μg/g. The films produced by extrusion with the lipid fraction of the fermented shrimp waste did not originate astaxanthin migration into the tested fatty food simulants. Further studies could be made in order to evaluate the capacity of these films in protecting packed food from oxidation.
- Active polylactic acid film incorporated with green tea extract: Development, characterization and effectivenessPublication . Martins, Carla; Vilarinho, Fernanda; Sanches-Silva, A.; Andrade, Mariana; Machado, A.; Vaz, M.F.; Ramos, F.A new antioxidant active packaging film has been developed based on polylactic acid (PLA) in which green tea extract (GTE) has been immobilized by extrusion. Two GTE concentrations were tested, 1% (w/w) and 2% (w/ w). Four GT samples were compared regarding their antioxidant capacity (by DPPH radical scavenging method and β-carotene bleaching method), total phenolics content (TPC) and total flavonoids content (TFC). The commercial GTE presented with highest antioxidant capacity by the DPPH radical assay (EC50=0.12 ± 0.00 mg/mL) and the highest TPC (416 ± 9.95 mg gallic acid equivalents (GAE)/g extract) and it was selected to be incorporated in the active film. Films were evaluated regarding their mechanical properties (e.g. tensile strength decreased 12% with the incorporation of GTE in the PLA matrix and strain at break increased 9.6 and 36% with the addition of 1 and 2% of GTE) and water vapour transmission rates (watervapour barrier properties improved with the addition of higher amounts of GTE). The study of the effectiveness of PLA/GTE films against lipid oxidation was performed by the following methods: peroxide value, p-anisidine value, thiobarbituric acid reactive substances (TBARS) assay and hexanal monitoring, after packaging smoked salmon slices during different storage times (0, 7, 15, 30, 45 and 60 days). The results showed that the incorporation of GTE in the PLA films protects the smoked salmon from lipid oxidation in the different storage times tested. However, additional studies should be performed to better understand the GTE mechanism of action as the results suggest a pro-oxidant effect of PLA/GTE 2% after 60 days of storage and to evaluate the potential antimicrobial activity of active films.
- Activity of chitosan films against different microorganismsPublication . Sanches-Silva, A.; Maia, C.; Furtado, R.; Ribeiro, T.; Paseiro, P.; Sendón, R.; Rodríguez-Bernaldo de Quirós, A.; López-Cervantes, J.; Sánchez-Machado, D.I.; Bueno, C.; Soto Valdez, H.; Angulo, I.; Aurrekoetxea, G.P.; Bilbao, A.; Costa, H.S.Chitosan is a hydrophilic polysaccharide which derives from chitin by deacetylation. It has several applications, namely as a film that can be applied to preserve the quality and increase the shelf-life of food. Chitosan is insoluble in most solvents but it is soluble in dilute organic acids such as formic acid and acetic acid[1]. The properties of chitosan depend on the degree of deacetylation (DA) and molecular weight (MW). A broad antimicrobial activity has been attributed to chitosan, either for gram-negative, gram-positive bacteria and fungi. The aim of the present study is to evaluate the antimicrobial activity of a chitosan film prepared by casting. The chitosan was obtained from shrimp waste collected from shrimp processing factories of South Sonora (Mexico). Four bacteria (Bacillus cereus; Escherichia coli; Staphylococcus aureus and Listeria monocytogenes) and one fungus (Botrytis cinerea) were evaluated. Although L. monocytogenes and B. cinerea growth was not inhibited by the chitosan film, results showed a clear growth-inhibitory effect, at the two bacteria concentration levels tested, for B. Cereus, E. coli and S. aureus. Different antibacterial mechanisms have been proposed to explain chitosan antimicrobial activity[2-3]: i) chitosan may form an external barrier which inhibits essential nutrients adsorption; ii) chitosan can also penetrate the microbial cell, disturbing the metabolism of the cell by inhibiting the mRNA and protein synthesis; iii) chitosan may have an ionic surface interaction with the bacteria originating wall cell leakage. Although these mechanisms may take place simultaneously, the antimicrobial activity may also depend on the properties of chitosan (DA and MW).
- Advances in phenolic compounds analysis of aromatic herbs and their potential applications.Publication . Carvalho-Costa, D.; Costa, H.S.; Reis, A.R.; Albuquerque, T.G.; Castilho, M.C.; Ramos, F.; Machado, A.V.; Sanches-Silva, A.; PhenolicIntroduction: Herbs can be considered important sources of antioxidants and have a long history of medicinal and culinary applications. The use of plants as sources of antioxidants for nutritional and preservation purposes in the food industry is currently growing. Materials and Methods: An extensive bibliographic review on the methods for analysis of phenolic compounds present in herbs was carried out. Results, Discussion and Conclusion: Plant derived phenolic compounds can be divided in four groups: phenolic acids, phenolic diterpenes, flavonoids and volatile compounds. Considering the first three groups, the identification and quantification of the compounds in the literature is accomplished using High Performance Liquid Chromatography while for volatile compounds, the identification and quantification is accomplished with Gas Chromatography. Several herbs, such as sage (Salvia officinalis), thyme (Thymus vulgaris), rosemary (Rosmarinus officinalis), oregano (Origanum majorana), dandelion (Taraxacum officinale), peppermint (Mentha piperita) and basil (Ocimum basilicum) were analyzed in different studies regarding their phenolic compounds. The major phenolic acids found in herbs were ferulic, caffeic, neochlorogenic and rosmarinic. In terms of phenolic diterpenes, carnosol, rosmanol and carnosic acid were the most reported. Regarding flavonoids, luteolin, quercetin and apigenin were predominant. Concerning volatile compounds, thymol, carvacrol and eugenol were the most common. The herbs with more antioxidant potential regarding their composition on phenolic compounds were compared and the potential of utilisation of these food matrices for newer applications such as active packaging was discussed.
- Aloe vera: Ancient knowledge with new frontiersPublication . Sanchez-Machado, D.; Lopez-Cervantes, J.; Sendón, R.; Sanches-Silva, A.Background: There are many plants with interesting pharmaceutical activities but Aloe vera is probably the most applied medicinal plant worldwide. Since biblical times, aloe has been used for its purgative effect, skin disorders healing and beauty treatments. Scope and approach: For this study, an extensive review on Aloe vera was carried out, including its main uses, components (both nutrients and bioactives), biological activities, and applications. Future trends were also assessed. Key findings and conclusions: Aloe possesses numerous activities including, anticancer, antioxidant, antimicrobial, antiallergic, anti-inflammatory, immunomodulatory, hepatoprotective, antiulcer and antidiabetic. Some of these activities are due to the presence of polysaccharides (acemamman; glucomannan). A wide variety of commercial products based on Aloe vera are available on the market. However, the knowledge of the relationship between biological and therapeutic properties and its components has to be clearly defined in order to know the exact mechanism of action to develop effective new products, namely pharmaceuticals. The knowledge of the factors that affect Aloe vera variability, such as processing conditions, is also of great importance to be able to standardize the final products.
- An HPLC Procedure for the Quantification of Aloin in Latex and Gel from Aloe barbadensis LeavesPublication . Sánchez-Machado, D.I.; López-Cervantes, J.; Mariscal-Domínguez, M.F.; Cruz-Flores, P.; Campas-Baypoli, O.N.; Cantú-Soto, E.U.; Sanches-Silva, A.Aloin is an anthraquinone-C-glycoside present in Aloe vera. This compound is extremely variable among different species and highly depends on the growing conditions of the plants. The quantification of aloin in different extraction preparations has been a frequent problem due to the high instability of the compound. The aim of the present study is to develop and validated an analytical method for aloin detection in fresh and dry samples of Aloe barbadensis gel and latex using high performance liquid chromatography coupled to a diode array detector (HPLC-DAD). Phosphate buffered saline (pH 3) was selected as the extraction solvent. The aloin was separated using a Zorbax Eclipse AAA column (4.6 × 150 mm) at 35°C, and water and acetonitrile were used as the mobile phase at a flow rate of 0.9 mL/min. The linearity was satisfactory with a correlation coefficient greater than 0.999. Under these conditions, the method precision (relative standard deviation) was 3.71% for FL, 4.41% for dry latex, 0.81% for fresh gel and 4.42% for dry gel samples. Aloe latex was determined to have a greater amount of aloin than aloe gel. The method validation was satisfactory and exhibited adequate linearity, repeatability and accuracy.
- An overview of Portuguese traditional foods with quality product designationsPublication . Abuquerque, T.G.; Sanches-Silva, A.; Santos, F.; Costa, H.S.Introduction. Traditional foods constitute an important part of the culture, history, identity, heritage and local economy of a region or country and they are key elements of the dietary patterns of each country [1]. These foods are commonly perceived as foods that have been consumed locally or regionally for a long time and the methods of preparation of such foods have been passed from generation to generation [2]. The Portuguese cuisine is characterized by a variety of rich, filling and fully-flavoured dishes. It is a Mediterranean cuisine, with Atlantic characteristics (high consumption of fish and seafood) and influence from different places around the world. The cuisine across Portuguese regions and islands is varied [3]. In 1992, the European Union (EU) created quality product designation systems, including Protected Designation of Origin (PDO), Protected Geographical Indication (PGI) and Traditional Speciality Guaranteed (TSG), which protect registered traditional foods and enable producers to market distinctive high-quality regional products [4, 5]. In this study a review among Portuguese traditional foods with quality product designation has been carried out. Results. Our results show that up to now 116 traditional foods have been registered in the EU, from which 58 are PDO and 58 are PGI. With respect to TSG until now only 1 traditional food has applied for this denomination. According to the DOOR database (http://ec.europa.eu/agriculture/quality/door) foods are divided into classes. Conclusions. A great variability of Portuguese traditional foods has been already registered as PDO or PGI. Nevertheless, some of these foods have never been characterized with respect to the nutritional composition and bioactive compounds content. This review aims to compile and up-to-date information of the Portuguese traditional foods with quality product designations and to increase interest among food researchers, manufacturers and consumers on these foods.
- An update on potato crisps contents of moisture, fat, salt and fatty acids (including trans-fatty acids) with special emphasis on new oils/fats used for fryingPublication . Albuquerque, T.G.; Sanches-Silva, A.; Santos, L.; Costa, H.S.Eighteen brands of potato crisps, frequently consumed, were analyzed to establish their nutritional value in relation to salt, fat and fatty acid (FA) composition. The purpose of the present study was to determine moisture, total fat, salt contents and FA profiles (including trans-FAs), and to identify the oil/fat used for frying of the 18 brands of potato crisps. Our results show that salt content ranged from 0.127 to 2.77 g/100 g and total fat content of potato crisps varied between 20.0 and 42.8 g/100 g. With respect to FAs analysis, palmitic acid (C16:0), oleic acid (C18:1) and linoleic acid (C18:2) were the major FAs found in the analyzed potato crisps. It is clear from our work that nowadays most potato crisps are currently produced using oils with high contents in unsaturated FAs, which can be considered as healthier from a nutritional point of view. Nevertheless, some brands of potato crisps still use palm oil or a blend of palm oil and other fats/oils, which are very rich in saturated FAs.
- Analysis of Carotenoids, Vitamins and Folates in Traditional Foods from Black Sea AreaPublication . Sanches-Silva, A.; Albuquerque, T.G.; Ribeiro, T.; Valente, A.; Finglas, P.; Flores, A.C.; Santos, M.; D’Antuono, L.F.; Costa, H.S.; on behalf of the BaSeFood Black Sea area partnersNowadays, consumers are much more aware of nutritional composition and show especially interest in compounds with putative health benefits. Therefore, in the last few years, great attention has been devoted to the study of bioactive compounds in order to promote the consumption of traditional foods. The European project BaSeFood (Sustainable Exploitation of Bioactive Components Black Sea Area Traditional Foods) aims to study the traditional foods from the Black Sea Area, namely their nutritional and bioactive composition. In the frame of this project, the present work has analysed carotenoids, vitamins and folates in 33 traditional foods. Carotenoids and retinol and -tocopherol were extracted from samples with hexane/ethanol (4:3, v/v) and quantified by Ultra-high Pressure Liquid Chromatography (UPLC) with diode array detection (DAD). Some samples required saponification with methanolic KOH prior to chromatographic analysis. In general, the most abundant carotenoid was β-carotene. Most of the samples contain -tocopherol and do not present retinol. In order to quantify L-ascorbic acid, samples were stabilized with perchloric acid and metaphosphoric acid in ultrapure water. After dilution with mobile phase, samples were quantified by High Performance LC (HPLC)-DAD. One of the samples with highest L-ascorbic content was fruit of the evergreen cherry laurel (29.7 mg/100 g). Vitamin B2 was extracted after acid hydrolysis followed by dephosphorylation and HPLC with fluorescence detection (method EN 14152:2003, accredited according to ISO 17025). The determination of the total folate content in foodstuffs was carried out by a microbiological assay (EN 14131:2003, accredited according to ISO 17025). One of the highest vitamin B2 and total folate levels was found for roasted sunflower seeds (0.19 mg and 113 µg per 100 g of edible portion, respectively).