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33 result(s) for "G. Sotelo, Carmen"
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Advances in the analysis of complex food matrices: Species identification in surimi-based products using Next Generation Sequencing technologies
The Next Generation Sequencing (NGS) technologies represent a turning point in the food inspection field, particularly for species identification in matrices composed of a blend of two or more species. In this study NGS technologies were applied by testing the usefulness of the Ion Torrent Personal Genome Machine (PGM) in seafood traceability. Sixteen commercial surimi samples produced both in EU and non-EU countries were analysed. Libraries were prepared using a universal primer pair able to amplify a short 16SrRNA fragment from a wide range of fish and cephalopod species. The mislabelling rate of the samples was also evaluated. Overall, DNA from 13 families, 19 genera and 16 species of fish, and from 3 families, 3 genera and 3 species of cephalopods was found with the analysis. Samples produced in non-EU countries exhibited a higher variability in their composition. 37.5% of the surimi products were found to be mislabelled. Among them, 25% voluntary declared a species different from those identified and 25% (all produced in non-EU countries) did not report the presence of molluscs on the label, posing a potential health threat for allergic consumers. The use of vulnerable species was also proved. Although the protocol should be further optimized, PGM platform proved to be a useful tool for the analysis of complex, highly processed products.
Collagen Extraction Optimization from the Skin of the Small-Spotted Catshark (S. canicula) by Response Surface Methodology
The small-spotted catshark is one of the most abundant elasmobranchs in the Northeastern Atlantic Ocean. Although its landings are devoted for human consumption, in general this species has low commercial value with high discard rates, reaching 100% in some European fisheries. The reduction of post-harvest losses (discards and by-products) by promotion of a full use of fishing captures is one of the main goals of EU fishing policies. As marine collagens are increasingly used as alternatives to mammalian collagens for cosmetics, tissue engineering, etc., fish skins represent an excellent and abundant source for obtaining this biomolecule. The aim of this study was to analyze the influence of chemical treatment concentration, temperature and time on the extractability of skin collagen from this species. Two experimental designs, one for each of the main stages of the process, were performed by means of Response Surface Methodology (RSM). The combined effect of NaOH concentration, time and temperature on the amount of collagen recovered in the first stage of the collagen extraction procedure was studied. Then, skins treated under optimal NaOH conditions were subjected to a second experimental design, to study the combined effect of AcOH concentration, time and temperature on the collagen recovery by means of yield, amino acid content and SDS-PAGE characterization. Values of independent variables maximizing collagen recovery were 4 °C, 2 h and 0.1 M NaOH (pre-treatment) and 25 °C, 34 h and 1 M AcOH (collagen extraction).
Tuna labels matter in Europe: Mislabelling rates in different tuna products
Tuna fisheries and processing represent economic activities of paramount importance around the world. Most of these products are traded for human consumption and in general are highly demanded commodities. However, not all tuna products achieve the same market price, some consumers are willing to pay a huge amount of money for certain species (i.e. Japanese market for Bluefin tuna) while other species are rather affordable (i.e. Skipjack tuna), therefore mislabelling has been observed frequently. We collected and analysed 545 tuna samples in six European countries, including fresh, frozen and canned products, and we have investigated whether or not these products were correctly labelled under European and national legislations. We found an overall mislabelling rate of 6.79%; in particular, 6.70% of the fresh and frozen tuna products and 7.84% of canned tuna were mislabelled, and only in the case of fresh and frozen tuna samples significant differences among countries were found. Mislabelling rates for Atlantic Bluefin tuna labelled products were very high, ranging from 50 up to 100%. In general, mislabelling was higher when specific names were included in the labels. The \"tuna\" umbrella term is a very popular one with consumers, but also one that remains vulnerable to ambiguity, hampering efforts towards market transparency and with potential negative consequences to the adequate management of tuna species stocks.
Production, Characterization, and Bioactivity of Fish Protein Hydrolysates from Aquaculture Turbot (Scophthalmus maximus) Wastes
The valorization of wastes generated in the processing of farmed fish is currently an issue of extreme relevance for the industry, aiming to accomplish the objectives of circular bioeconomy. In the present report, turbot (Scophthalmus maximus) by-products were subjected to Alcalase hydrolysis under the optimal conditions initially defined by response surface methodology. All the fish protein hydrolysates (FPHs) showed a high yield of digestion (>83%), very remarkable degrees of hydrolysis (30–37%), high content of soluble protein (>62 g/L), an excellent profile of amino acids, and almost total in vitro digestibility (higher than 92%). Antioxidant and antihypertensive activities were analyzed in all cases, viscera hydrolysates being the most active. The range of average molecular weights (Mw) of turbot hydrolysates varied from 1200 to 1669 Da, and peptide size distribution showed that the hydrolysate of viscera had the highest content of peptides above 1000 Da and below 200 Da.
Effect of Fish Collagen Hydrolysates on Type I Collagen mRNA Levels of Human Dermal Fibroblast Culture
Fish discards and subproducts may represent an important source of raw material, not only for the food industry, but for other different kind of industries, such as the nutraceutical and cosmetic industries. Collagen, which is mainly obtained from animal skins, is an important structural protein in the animal kingdom having many different applications. It is well known that fish skins constitute a significant subproduct in the fishery industry, especially in the case of some species, where fish skins may represent up to 20% of the total body weight of fish. Peptides from collagen hydrolysates have been described to be useful for preventing skin aging and osteoarthritis, however, the mechanism for these biological activities is not well known. Fibroblasts are the main cell types involved in the collagen synthesis, and in the present work, human dermal fibroblasts have been exposed to the treatment of collagen peptides of two different molecular weight ranges. Results show that higher molecular weight collagen peptides produce higher synthesis of collagen type I mRNA and, therefore, it may suggest that prior molecular weight selection may be an important step to maximize the effect of collagen hydrolysates on collagen type I synthesis by dermal fibroblasts.
Low mislabeling rates indicate marked improvements in European seafood market operations
Over the span of a decade, genetic identification methods have progressively exposed the inadequacies of the seafood supply chain, revealing previously unrecognized levels of seafood fraud, raising awareness among the public, and serving as a warning to industry that malpractice will be detected. Here we present the outcome of the latest and largest multi-species, transnational survey of fish labeling accuracy to date, which demonstrates an apparent sudden reduction of seafood mislabeling in Europe. We argue that recent efforts in legislation, governance, and outreach have had a positive impact on industry regulation. Coordinated, technology-based, policy-oriented actions can play a pivotal role in shaping a transparent, sustainable global seafood market and in bolstering healthier oceans.
The Influence of DNA Extraction Methods on Species Identification Results of Seafood Products
In terms of species identification, the ultimate aim of extracting DNA is the subsequent amplification of the selected marker; therefore, the quality and quantity of the extracted DNA must be sufficient for PCR-based methods. The purpose of this study is to compare five DNA extraction methods according to the parameters of quantity, quality and simplicity, among others, in order to determine the most suitable method for identification for Cephalopoda, Gadiformes and Pleuronectiformes. The Wizard DNA clean-up system kit (Promega), MPure-12TM automated nucleic acid purification system (MP Biomedicals), Chelex 100 resin (Biorad), DNeasy blood and tissue kit (Qiagen) and a swab method were examined. The obtained DNA quantity was determined by fluorescence, and quality was evaluated with ratios of absorbance of A260/A280 and A260/A230 by agarose gel visualization of the extracts and by analyzing the success of PCR amplifications of 720 bp fragments of cytochrome c oxidase I (COI) for Cephalopods and 465 bp fragments of cytochrome b for Gadiformes and Pleuronectiformes. Statistical results confirmed significant differences between the tested methods according to yield, efficiency and purity and no significant differences with respect to the species employed. The best yields were obtained with the Wizard kit, whereas other methods stand out in terms of their affordability (Chelex) and automation (Mpure).
Development of a Ready-to-Eat Fish Product Enriched with Fish Oil Entrapped in a κ-Carrageenan Egg White Fish Protein Hydrolysate Dry Powder
This work describes the development of a ready-to-eat (RTE) product based on an equal mixture of fish mince from three undervalued fish species with different fat contents and protein gelling capacity, which was enriched with fish oil entrapped in a κ-carrageenan egg white fish protein hydrolysate powder, obtained by either spray drying (SD) or heat drying (HD) at 80 °C (HD80). Previously, the spray-dried (SD) powder and heat-dried powders obtained at 45 °C, 60 °C and 80 °C (HD45, HD60 and HD80) were characterised in terms of water solubility, lipid oxidation (TBARS), hygroscopicity and ζ potential. All HD powders showed higher hygroscopicity and lower TBARS than the SD powder. The dry powder was incorporated into a blend composed of salt-ground batter and raw mince to improve binding and textural properties. Changes in water-holding capacity, colour, shear strength and microorganisms were monitored during the processing steps. The RTE product presented a high protein content and a noticeable amount of long-chain ω-3 fatty acids. The use of undervalued fish species together with fish oil and a protein hydrolysate from fish waste contribute to improving the sustainability of fishery resources, being conducive to obtaining a potentially functional RTE product.
A Real-Time PCR Method for the Authentication of Common Cuttlefish (Sepia officinalis) in Food Products
Cephalopods are very relevant food resources. The common cuttlefish (Sepia officinalis) is highly appreciated by consumers and there is a lack of rapid methods for its authentication in food products. We introduce a new minor groove binding (MGB) TaqMan real-time PCR (Polymerase Chain Reaction) method for the authentication of S. officinalis in food products to amplify a 122 base pairs (bp) fragment of the mitochondrial COI (Cytochrome Oxidase I) region. Reference and commercial samples of S. officinalis showed a threshold cycle (Ct) mean of 14.40, while the rest of the species examined did not amplify, or showed a significantly different Ct (p < 0.001). The calculated efficiency of the system was 101%, and the minimum DNA quantity detected was 10−4 ng. No cross-reactivity was detected with any other species, thus, the designed method differentiates S. officinalis from other species of the genus Sepia and other cephalopod species and works for fresh, frozen, grilled, cooked and canned samples of Sepia spp. The method has proved to be reliable and rapid, and it may prove to be a useful tool for the control of fraud in cuttlefish products.
New Strategy to Cope with Common Fishery Policy Landing Obligation: Collagen Extraction from Skins and Bones of Undersized Hake (Merluccius merluccius)
In order to promote sustainable fishing practices within European fishing fleets and to avoid the large waste of valuable fish biomass through the practice of fish discarding, the new reform of the common fisheries policy includes the obligation of landing all species under total allowable catch (TAC) regulations. The new policy also prohibits the use of specimens under minimum conservation reference size for direct human cons38umption. In this context, it is necessary to find new uses for undersized fish, which might help to alleviate the costs associated with the landing obligation but without prompting the creation of a market. European hake (EH) (Merluccius merluccius), which is one of the most important commercial fish species for the Spanish fishing industry, with a total TAC for 2018 of 37,423 t, is used for this study. Consistent with the current policy framework and taking into account the commercial importance of this species, the aim of this work is to study a new strategy for the extraction of collagen from the skin and bone fraction of Merluccius merluccius undersized discards. Three collagen fractions are successfully isolated for the first time from the skin of M. merluccius skin and bone discarded raw material: acid-soluble collagen (ASC) fraction 1 and pepsin-soluble collagen (PSC) fraction 2 from the skin and ASC fraction 3 from bones. The total collagen yield of the process is 13.55 ± 3.18% in a dry basis (g collagen/100 g of skin and bone fraction (SBF)) and 47.80 ± 9.83% (g collagen/100 g of collagen determined by the hydroxyproline content in SBF). The three fractions are further characterized by using different physical and chemical analysis techniques, with the conclusion drawn that the triple helix structure is preserved in the three fractions, although ASC fractions (F1 and F3) present more or stronger hydrogen bonds than the PSC fraction (F2). With the process herein presented, deboned and skinned hake specimens could represent an interesting source of high quality type I collagen, which could be useful as a raw material for the biomedical, cosmetic, and nutraceutical industries.