Gelation properties of chicken myofibrillar protein induced by transglutaminase crosslinking

Gelation properties of chicken myofibrillar protein isolate (MPI) and the effect of microbial transglutaminase (MTG) were studied using a dynamic oscillatory rheometer and a texture analyzer. Final heating temperature had a great impact on gel stiffness and the maximum gel stiffness was obtained at 95 °C. pH and ionic strength also influenced gel stiffness and the maximum gel stiffness was achieved at pH 6, 0.9 M NaCl; however, less stiff gels were formed in 0.6 and 1.2 M NaCl. In the MPI concentration range of ∼0.5–5%, a positive correlation was observed between gel stiffness or gel peak force and MPI concentration. When MTG was included at levels of ∼0 to 12–15 U, positive linear relations were found between gel stiffness or peak force and MTG levels. However, negative correlations for these parameters were observed at higher MTG concentrations. When MTG level was greater than 15 U, gel stiffness or peak force tended to decrease. The improvement in gel strength or gel peak force for the MPI with inclusion of MTG suggested that some ε (γ-glutamyl) lysine (G-L) crosslinking occurred among myofibrillar molecules. Thus, MTG is useful in improving gelation properties of heat-induced MPI gel and provides new opportunities to expand the utilization of low value meat in muscle foods.

► We study the gelation of isolated chicken myofibrillar protein (MPI).
► Maximum gel stiffness occurs at pH 6, 0.9 M NaCl, 95 °C.
► Adding up to 15 U of microbial transglutaminase (MTG) increases gel stiffness.
► More than 15 U of MTG decreases gel stiffness.
► MTG can improve the gelation properties of MPI.