CHANGE IN QUALITY OF PREHEATED GEL AND 2-STEP HEATED GEL FROM WALLEYEPOLLACK AND CHUM SALMON ON ADDITION OF MICROBIAL TRANSGLUTAINASE

Frozen surimis of walleye pollack and chum salmon were ground with 3% NaCl and 0.3% food additive containing microbial transglutaminase (TGa se). The salt-ground meats mere heated at 25 degrees C or 40 degrees C far various periods to prepare preheated gel and subsequently heated at 90 degrees C for 30 min to obtain two-step heated (kamaboko) gel. Q uality of the gels was evaluated from the changes in gel properties (b reaking strength and breaking strain) as a function of preheating time . Subunit composition of myofibrillar proteins in the gels was also an alyzed by SDS-PAGE and densitometry. Results were as follows: 1) Gel f ormation of the salt-ground meat from both frozen surimis was largely enhanced by the addition of TGase, 2) The characteristic gel forming p rofile of each salt-ground meat induced by heating at 25, 40 degrees C , and subsequent heating at 90 degrees C, changed nearly the same as w ith TGase. 3) The cross-linking reaction of myosin heavy chains marked ly proceeded in the preheating gels by the addition of TGase. During t he subsequent heating at 90 degrees C, the cross-linking reaction did not proceed further. It is evident that the kamaboko gel forming natur e of the salt-ground meats from walleye pollack; and chum salmon froze n surimis was essentially altered by the addition of TGase. The possib le non-covalent type forces between myofibrillar proteins contributing to gel formation in the presence and absence of TGase are discussed.