Effect of Microbial Transglutaminase on Thermal Gelation of Carp Actomyosin Sol

The heat-induced gelling properties of carp actomyosin sol containing 90 mg protein per g of sol at 0.5 M NaCl and pH 7.0 were investigated by dynamic rheological measurements, breaking strength measurements, and SDS-PAGE analyses. The results indicated that the sol was characterized by poor gel forming ability caused by the inherent properties of carp actomyosin, no setting response, and relatively strong non-proteolytic gel weakening (modori) around 53°C. Furthermore, at slow heating rate, it was found that myosin heavy chain was cleaved by a myofibril-bound proteinase(s). The addition of microbial transglutaminase could induce setting response to actomyosin sol; the extent of the response and resulting gel strength increased markedly with an increase in the transglutaminase activity level. The non-proteolytic modori was not reduced by the addition of transglutaminase.