EFFECT OF ULTRASONIC TREATMENT ON THE GEL STRENGTH OF TILAPIA (SAROTHERODON NILOTICA) SURIMI

Abstract

ABSTRACT The effect of ultrasonic treatment on the gel strength of tilapia (Sarotherodon nilotica) surimi was investigated. Prior to chopping, surimi was treated by ultrasound, 250 W at 28 kHz, 45 kHz, and 100 kHz, respectively. The results showed that the breaking force, deformation, and gel strength of surimi gels prepared from ultrasonic‐treated (UT) surimi were significantly (P < 0.05) higher than those of the control. A possible reason for the result was that ultrasonic treatment led to a disruption of muscle tissue. This was supported by the observation that the salt‐ or water‐soluble proteins of UT surimi were higher (P < 0.05) than those of the control; the microscope images; and the optimal chopping times for the maximum breaking force, deformation, and gel strength were longer than that adopted in the gel preparation; there were no new peaks produced in the SDS‐polyacrylamide gel electrophoresis of the UT surimi and the control.PRACTICAL APPLICATIONChopping is important for the preparation of surimi gel. The purpose of chopping is to disrupt muscle structure, permitting the muscle proteins to be effectively dissolved by salt and to form a stronger gel. Research has indicated that ultrasound can disrupt cell walls. Therefore, ultrasound was used with mechanical chopping to disrupt the muscle structure of tilapia surimi. This supplies a new method to process surimi.