Changes in protein compositions and textural properties of the muscle of skate fermented at 10°C

Chemical properties such as pH, ammonia nitrogen, total volatile base nitrogen, trimethylamine nitrogen, protein composition, and free amino acids composition and textural property were investigated for skate muscle subjected to fermentation at 10°C for 14 days. The values of pH, TVBN, TMAN, and ammonia nitrogen content significantly increased in skate muscle. Principal component analysis indicated a high correlation between changes in textural profiles and ammonia flavor and changes in muscle protein composition. In addition, SDS-PAGE of protein fractions showed that myofibrillar tended to aggregate into large polymers during fermentation. On the other hand, changes in trichloroacetic acid-soluble peptides and free amino acid content during fermentation indicated intensive degradation of muscle proteins. The variations in chemical properties and protein composition of skate muscle during fermentation reveal that decomposition and degradation of muscle proteins are important factors that influence the chemical composition and textural property of skate during fermentation at 10°C.