Effect of heat-treatment on the rheological properties of chum salmon Oncorhynchus keta muscle in association with the maturation
1990
Tsuji, K. (Hokkaido. Kushiro Fisheries Experiment Station (Japan)) | Kawai, Y.
The effect of hear-treatment on the viscosity of total protein (T-P) solution and rheological properties of muscle block of fall chum salmon (Oncorhynchus keta) were investigated in association with the commercial quality grade of the fish judged from the degree of nuptial coloration: S grade, silvery; A grade, slight nuptial coloration; B grade, moderate nuptial coloration; C grade, strong nuptial coloration; D grade, very strong nuptial coloration. S, A, B and C-graded fish were captured at coastal sea, and D-graded fish was captured in a river. T-P solution showed a non-Newtonian pseudo-plastic flow, and had a maximal value of apparent viscosity at 30-35 degrees C. The viscosity of T-P at 20 degrees C was correlated to the myofibrillar protein content in the protein of the higher grade fish. Unheated muscle became more tender, less elastic and more viscous with the lowering of the quality grade of fish. Muscle heated at 100 degrees C for 30 min also became more tender when lowering the quality grade. The elasticity of the heated muscle was not related to the quality grade. The heat-treatment of muscle made clearer the tendency of muscle tenderization when lowering the quality grade. It was considered that the rheology of muscle might be affected by the decrease in protein content, changes in protein composition, and the decomposition of protein by a stronger protease activity in the muscle during spawning migration
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