Biochemical and morphological changes in muscular tissue of pond fish in the process of autolytic transformations

Physical and chemical processes in muscular tissue of pond fish are considered in the process of storage. The muscle contraction appears mainly because of the myofibrils activity that utilizes energy of the sarcoplasm substances. Intense disintegration of glycogen causes sharp acidification (pH decreasing) in the muscular tissue that affects on chemical composition and physical-colloidal structure of proteins. Hardening of the muscular tissue is observed in the first hours of storage because of the proteins transformation to actin and myosin in insoluble actomyosin complex. The highest level of actomyosin is observed in the first 3–5 hours that is the evidence of unstable rate of biochemical processes corresponded to changing activity of enzyme systems. Cumulative level of the actomyosin complex grows in the first 8 hours of storage for all investigated fish species. Organoleptic and technological characteristics of the fish meat improve significantly in the process of its maturation: the meat has no definite taste and smell in early stages of autolysis, but these properties appear in 3–4 days, depending on the storage temperature, due to enzymatic decomposition of proteins, peptides, nucleotides, carbohydrates, lipids, etc. Recommendations on storage are presented for certain groups of fish products in dependence on initial properties of raw materials.