EFFECT OF ULTRASONIC TREATMENT ON THE ACTIVITIES OF ENDOGENOUS TRANSGLUTAMINASE AND PROTEINASES IN TILAPIA (SAROTHERODON NILOTICA) SURIMI DURING GEL FORMATION

摘要

The effects of ultrasonic treatment (UT) on the activities of endogenous transglutaminase (TGase) and proteinases in tilapia surimi were investigated. Surimi paste set at 40C with or without UT, prior to heating at 90C, resulted in a significant (P < 0.05) increase in gel strength as setting time increased, the gel strength of surimi paste treated with UT was higher (P < 0.05) than that of the control. A decrease in the solubility of surimi gels with UT suggested that the UT increased the formation of non-disulfide covalent bonding which coincided with an increase in gel strength and a decrease in myosin heavy chain (MHC) polypeptide content. Surimi paste incubated at 65C with UT prior to heating at 90C resulted in a significant increase in gel strength (P < 0.05), compared with the control. A decrease in the trichloroacetic acid-soluble peptides of surimi gels with UT coincided with an increase in gel strength and more retained MHC, suggesting that the endogenous proteinases were deactivated by UT.

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