The impact of crucial protein degradation in intramuscular connective tissue on softening of ice‐stored grass carp (Ctenopharyngodon idella) fillets

Summary This study aimed to determine the role of intramuscular connective tissue (IMCT) in softening of ice‐stored grass carp ( Ctenopharyngodon idella ) fillet. The change in important proteins in IMCT and impact of IMCT destruction in fish softening were both investigated. The exogenous collagenase was used to differentiate the role of IMCT. Results showed that decorin, elastin and collagen in IMCT decreased by 71%, 48% and 54%, respectively. Decorin and elastin were mainly degraded in the primary stage, while collagen decreased mainly in the later stage. Then, IMCT destruction experiment showed that collagenase was quite effective for destruction of IMCT, while myofibre tissue was not affected. Subsequently, specific role of IMCT could be distinguished. Decrease in shear force became twofold faster in the collagenase group at the beginning than that in the control group, indicating a quite important role of IMCT in maintaining fish texture, especially in the primary stage of storage.