Transglutaminase Effects on Low Temperature Gelation of Fish Protein Sols

Myosin polymerization and formation of ɛ‐(γ‐glutamyl)lysine linkages were quantified in Alaska pollock surimi gels which contained no additive (control), or a commercial microbial transglutaminase (MTGase). As preincubation (“setting”) time at 25°C was increased, the gel strength of control and 0.2% MTGase‐added samples increased, with greater increases at higher MTGase levels. SDS‐PAGE and HPLC analyses showed increasing nondisulfide polymerization and ɛ‐(γ‐glutamyl)lysine dipeptide content, with increasing setting time and/or added MTGase. Content of ɛ‐(γ‐glutamyl)lysine dipeptide correlated with gel strength (shear stress) and shear modulus at failure (G f ) for these gels. Higher stresses were measured in samples containing 0.2% MTGase than in controls at corresponding levels of ɛ‐(γ‐glutamyl)lysine dipeptide, indicating that rate of myosin polymerization may affect ultimate gel strength.