Conformational Changes and Kinetic Study of Actomyosin from Silver Carp Surimi with Modified Starch–Sucrose Mixtures during Frozen Storage

Abstract

AbstractThe cryoprotective effects of modified starch–sucrose mixtures on silver carp surimi were compared with commercial cryoprotectant using the changes in gel strength and actomyosin conformation during frozen storage. Acetic acid esterification starch (AAES)‐sucrose maintained the maximum gel strength and Ca2+–ATPase activity throughout the frozen storage (P < 0.05). Hydroxypropylated starch (HS)‐sucrose showed a similar retention of Ca2+–ATPase activity (39.34%) and salt‐soluble protein (SSP) content (60.20%) to that of AAES–sucrose (40.14%, 63.89%, respectively) after 91 days of storage (P > 0.05). AAES–sucrose and HS–sucrose separately showed the best effect on depressing loss of total sulfhydryl content in the early 28 days and later 63 days. Therefore, they protected actomyosin structure more effectively than commercial cryoprotectant. The relationship of Ca2+–ATPase activity and SSP content with respect to storage time could be fitted with a first‐order model to predict the changes in fish protein structure during frozen storage (R2 > 0.99).Practical ApplicationsModified starch–sucrose mixtures tended to improve gel strength of frozen surimi, as well as effectively prevent conformational changes of actomyosin during long period of frozen storage at −20C. The effectiveness of acetic acid esterification starch (AAES)‐sucrose and hydroxypropylated starch (HS)‐sucrose seemed to be slightly evident than commercial cryoprotectant. Therefore, the application of AAES‐sucrose or HS‐sucrose in frozen surimi products could be popularized at reduced cost and more healthy quality.