Freshness assessment of grass carp (Ctenopharyngodon idellus) fillets during stroage at 4 °C by physicochemical, microbiological and sensorial evaluations

Abstract The freshness of commercial grass carp fillets stored at 4°C was estimated by physicochemical, microbiological and sensorial methods. Total volatile basic nitrogen, trimethylamine, thiobarbituric acid, trichloroacetic acid (TCA)‐soluble peptide, water loss, hypoxanthine, inosine and K value increased significantly ( P < 0.05), while the content of inosine monophosphate was sharply decreased during storage period. Putrescine and histamine were the major amines and their concentrations were significantly ( P < 0.05) higher than other amines at the end of storage period. With regard to the texture profile analysis, the values of texture parameters (including hardness, gumminess, cohesiveness, chewiness and resilience) decreased rapidly within the first 7 days, and then changed slowly until the end of storage, meanwhile, the variation of springiness was not significant during the whole storage period. All the tested microorganisms increased continuously and H 2 S‐producing bacteria (including Shewanella putrefaciens ) was one of major specific spoilage organisms in refrigerated grass carp fillet. Furthermore, sensory analysis of odor and overall acceptability exhibited negative correlations with storage time (−0.96 and −0.94), which was a reflection of the fillets' loss of freshness. Based on the comprehensive results of physicochemical, microbiological and sensory evaluations, grass carp fillets had a shelf life of approximately 10 days during refrigerated storage. Practical applications Grass carp is one of the most important commercial freshwater fish in China and it is popular in market because of its palatability, nutritional characteristic and low price. As we all know, postmortem fish is highly perishable. Investigation of quality changes of refrigerated grass carp is of great significance to fillets' cold‐chain delivery. The quality analysis of refrigerated grass carp fillet will contribute to fishermen and processors in establishing better processing and distribution strategies.