Improvement of Surimi Gel Quality Using Protein Cross-Linker, Hydrocolloids and Protease Inhibitor

Abstract

Surimi and its products have been consumed widely, especially in Japan and Southeast Asia. Market value and consumer acceptability are mainly determined by the textural properties of surimi gel. Textural and gelling properties are governed by the type of fish, lipid content, processing conditions, and presence of endogenous protease and transglutaminase. In addition, several additives such as protein cross-linkers, hydrocolloids, protease inhibitors, etc. have been used in surimi to improve their gelling properties. Cross-linking is the promising method for protein modification to obtain desirable surimi-based gel products possessing unique textural properties. Endogenous transglutaminase (TGase) plays a profound role in protein cross-linking during setting in surimi paste. For surimi from fish with low setting phenomenon, microbial TGase (MTGase) has been widely used. Plant polyphenols have also been employed for protein crosslinking to strengthen the surimi gel. Polysaccharides mainly the hydrocolloids also strengthen the gel network and increase water holding capacity (WHC) of gel. During heating, endogenous heatactivated proteases that are firmly attached to muscle proteins are active in hydrolyzing myofibrillar proteins. This results in a weaker gel with low WHC. Protease inhibitors form plants as well animals could impede the protease activity, thus maintaining the myofibrillar proteins responsible for the gelation. In addition to the additives, processing methods such as highpressure technology or ohmic heating in combination with those additives have a positive impact on the gel properties. For this review, the role of various kinds of additives namely protein crosslinkers, hydrocolloids and protease inhibitors in surimi gel improvement was revisited.