Acronym TEXBREAM
Category
Marine Biotechnology
Title Post-mortem changes in gilthead sea bream muscle proteins: its implications to flesh texture Programme Nat. Programme (supported by ESIF)
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National-European Coordinator Jorge Dias Coordinator email jorgedias@sparos.pt
Coordinator institution
CCMAR - Center of Marine Sciences (Portugal)
Institutions involved
CIIMAR - Interdisciplinary Centre of Marine and Environmental Research (Portugal) ,
IPMA - Portuguese Institute for Sea and Atmosphere (Portugal) ,
Start year 2008 End year 2011 Funding (€) € 188,327 Website https://www.fct.pt/apoios/projectos/consulta/vglobal_projecto?idProjecto=70858&idElemConcurso=860 Summary Despite the higher health value of farmed fish, studies with gilthead sea bream and European seabass show that consumers prefer wild caught to farmed fish because of their superior organoleptic qualities and firmer texture. Texture is considered to be one of the most important quality attributes in fish. Flesh texture in fish is a complex set of intrinsic traits such as the muscle chemical composition (fat content and fatty acid profile, glycogen stores) and muscle cellularity and is strongly influenced by a variety of extrinsic factors such as pre- and post-slaughter handling procedures. During the post-mortem ageing of muscle under chilled conditions, degradation of muscle proteins and connective tissue contributes to the rapid softening of the flesh. Known post-mortem protein changes in fish muscle include the degradation of some large cytoskeletal proteins, such as desmin, alfa-connectin and alfa-actinin, whereas the profile of sarcoplasmic proteins seem to be rather unaffected by spoilage. The main myofibrillar proteolysis is attributed to endogenous protease activity, namely the calpains, cathepsins and collagenase enzymes. Despite the great amount of knowledge generated on protein degradation during post-mortem storage of fish, there are still many uncertainties regarding how the degradation of specific proteins relates to flesh firmness. A variety of ante-mortem factors such as nutritional factors, feeding strategies, pre-slaughter handling stress and slaughtering method have all been associated to muscle texture changes in fish. But again, the mechanisms underlying such changes remain poorly understood. It is now clear that flesh quality traits are complex and multigenic in nature. Hence, it is felt that a detailed characterisation of post-mortem changes in fish muscle would benefit from experimental approaches and technologies aimed at parallel analyses of numerous genes and proteins simultaneously. Proteomics offers a comprehensive approach to study biochemical systems by expanding the investigation from single proteins to a wide range of proteins at once. Thus, by means of expression proteomics we will be able to identify a protein cluster that has changed in the tissues in response to a given physiological or nutritional state. The main objective of this project is to apply proteome analysis to study the alterations in sea bream muscle proteins during various post-mortem stages. The processes occurring during post-mortem metabolism are known to lead to characteristic changes in the texture of fish muscle. Therefore, it was found essential to include also other more conventional evaluation criteria, such as detailed characterisation of endogenous protease activities, muscle cellularity, sensory evaluation and instrumental texture analysis. The experimental variables identified in this project to be evaluated as relevant modulators of flesh firmness in fish were: slaughtering stress, starvation period prior to slaughter and dietary factors, such as plant-protein and vegetable oil rich diets. In general, the successful accomplishment of this project will provide us with new and valuable information regarding the changes in protein expression that occur during the early post-mortem stages of fish muscle (at both pre- and post-rigor mortis stages). The use of proteome analysis to track such changes may reveal and allow the identification of presently unknown protein degradations occurring in post-mortem flesh in fish. We are confident that the association of proteome analysis with the broad range of biochemical criteria chosen will allow us an integrative view on the mechanisms related with flesh softening in fish.
The main objective of the project was to characterize and elucidate how post-mortem metabolic changes and muscle proteins degradation relates to a major flesh quality trait, namely texture. To attain this general objective, several experimental variables were evaluated as modulators of flesh firmness in fish. These variables are: (1) Harvesting and slaughtering practices; (2) Dietary factors, such as the use of plant-protein and vegetable oil rich diets and the use of feeding strategies to modulate energy storage and buffer capacity in fish muscle. By means of a multidisciplinary approach, associating the use of proteome analysis to track the changes in protein expression occurring during in post-mortem muscle and traditional texture assessment criteria, such as sensory evaluation, instrumental measurements, muscle cellularity, endogenous protease activities, we intended to gain a general view on the mechanisms related with flesh softening in fish. The project was designed to allow the evaluation of a broad range of parameters in both pre- and post-rigor mortis stages.
Keywords
Fish;
Seabream;
Diets;
Protein;
Quality;
Marine Region
76
Not associated to marine areas
0
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