Influence of storage and heat treatment processes of black grenadier on quality indicators of raw fish and finished product

The purpose of research is to study the dependence of the quality of raw and finished products from a promising for fishing and processing deep-sea fish species - black grenadier Coryphaenoides acrolepis - on processing and storage conditions. The fish was caught in the South Kuril subzone of the Sea of Okhotsk at a depth of 1000 m. Tasks: determination of the size-mass composition, functional-technological and physical and chemical properties of muscle tissue of two size groups of this species, the study of the rheological parameters of raw fish before and after heat treatment at various cutting and storage methods, as well as repeated freezing / thawing. The study was conducted in the laboratory of the Research Institute of Innovative Biotechnologies of the Far Eastern State Technical Fisheries University in Vladivostok. The following indicators were used as the main criteria for evaluating the functional and technological properties of fish muscle tissue: watering coefficient (Ko); protein-water ratio (BVK); structure formation coefficient (Kst); conditional protein coefficient (Kb); lipid-protein coefficient (Kf). The absence of significant differences in all studied parameters in two size groups before and after heat treatment is shown. Storage of carcasses and fillets in a catering establishment for 3 months to a greater extent affected the quality of carcasses in the direction of increasing the strength of muscle tissue. Repeated multiple freezing, used to search for the cause of the appearance of specimens with a rubbery consistency of muscle tissue, showed the absence of causal relationships of these processes and was confirmed by studies of changes in the molecular weight distribution of protein fractions of muscle tissue before and after storage by polyacrylamide gel electrophoresis.