Relationship Between the Starch Granule Structure and the Textural Properties of Heat-Induced Surimi Gels

Starch, used as a textural additive in heat-induced surimi gel, influences the rigidity of the protein gel matrix and hence the gel strength according to its botanical characteristics. The present study focuses on the correlations existing between the textural properties of heatind uced surimi gels obtained by physical measurements and the characteristics of different commercial starches. The gelatinization temperature of starch was closely related to the expressible moisture, work to fracture, and elongation. Behaviour of starchy components during thermal processing and its relationship to fish protein gel matrix were studied by light and electron microscopy. These studies showed differences in starch swelling, amylose leaching , and amylopectin behaviour depending on water intake. Cryo-scanning electron microscopy revealed structural features which have never been observed by the classical cyto-techniques

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

Labelfish – towards a universal methodology to combat seafood fraud

44th WEFTA meeting, 9-11 June 2014, Bilbao (Spain)Fraud refers to deliberate actions intended for the misleading of consumers in different ways. In the case of seafood, most of the time the term fraud involves the substitution of valuable species by others of lower price, therefore meaning an economic loss for consumers, but also mislabelling can hide other malpractices such as illegal capture procedures. Traceability of fish and seafood is mandatory since 2005 within the EU. Full implementation requires an adequate management of information and also the availability of techniques, which allow the verification of the information transmitted. These are essential tools to combat food fraud, however recent cases have shown that although legislation and techniques are available there are still some crisis related with food fraud which merit a deep evaluation and analysis of the problem . LABELFISH is a project funded by the Atlantic Area Programme and includes participants of six countries in Europe, mainly from the Atlantic area, which are characterized by an intense economic and social relationship with marine resources. One of the main aims of LABELFISH is the establishment of a network of laboratories and national control bodies with experience and interest in seafood labelling and traceability. The objectives include the level of implementation of traceability schemes in most important European seafood value chains, the analysis and detection of possible examples of seafood fraud across Europe, the consumers perception about seafood labelling, the current ethodologies used for controlling the veracity of seafood labels, and how to propose harmonized methodologies for the adequate control of seafood labelling in the European Union. This talk will focus on the Labelfish aspects related with the harmonization of fish species identification methodologies in the context of LABELFISHN

A literature review of helminth parasites in the sea lamprey Petromyzon marinus (Petromyzontidaeà, with a field-study in postmetamorphics from French rivers and coastal waters

International audienc

A literature review of helminth parasites in the sea lamprey Petromyzon marinus (Petromyzontidaeà, with a field-study in postmetamorphics from French rivers and coastal waters

International audienc

Methods for identifying and interpreting sex‐linked SNP markers and carrying out sex assignment: application to thornback ray ( Raja clavata )

Sex determining modes remain unknown in numerous species, notably in fishes, in which a variety of modalities have been reported. Additionally, non‐invasive individual sexing is problematic for species without external sex attributes or for early life stages, requiring cytogenetic or molecular analyses when sex chromosomes or sex‐linked markers have been characterized. Genomics now provide a means to achieve this. Here, we review common sex‐determination systems and corresponding statistical methods for identifying sex‐linked genetic markers and their use for sex assignment, focusing on single nucleotide polymorphism (SNP) markers derived from reduced representation sequencing methods. We demonstrate the dependence of expected sex assignment error on the number of sex‐linked SNPs and minor allele frequency. The application of three methods was made here: i) identification of heterozygote excess in one sex, ii) F ST outlier analysis between the two sexes and iii) neuronal net modelling. These methods were applied to a large SNP dataset (4604 SNPs) for 1680 thornback rays (Raja clavata ). Using method i), nineteen putative sex‐linked SNPs were identified. Comparison with the reference genome of a related species (Amblyraja radiata ) indicated that all 19 SNPs are likely located on the same chromosome. These results suggest that thornback ray has a XX/XY sex‐determination system. Method ii) identified eight SNPs probably located on different chromosomes. Method i) led to the lowest sex assignment error among the three methods (4.2% error for females and 3.7% for males)