Effect of high pressure and setting condition on physico-chemical, structural and functional characteristics of transglutaminase mediated fish gels

Abstract

Application of High pressure and low temperature setting condition on microbial transglutaminase (MTGase) mediated gelation was studied against conventional cooking in pink perch mince. A high pressure of 250 MPa was given to pink perch mince samples added with and without MTGase enzyme, for a holding time of 12 min and a setting condition of 25 °C for 30 min was given prior and after the treatments. Nine random experiments (T1 to T9) were made against high pressure and cooking and analysed its textural and functional properties. Addition of MTGase and setting conditions had significant effect on the textural properties of the both samples especially in inducing the gel strength. Reduction in total and reactive sulfhydryl groups observed was due to the formation of disulfide linkages, which was found more in T6 to T9. Setting condition had significant effect on protein hydrophobicity in both pressure and heat induced gels. No significant variation in the Ca2+-ATPase enzyme activity was observed among treatments. SEM images revealed more closed and dense fibrous network in samples with enzyme (T6 to T9), due to more protein polymerisation. So MTGase enzyme along with pressure treatment enhanced the conformational stability and produce stronger networks through the formation of non sulfide bonds between proteins and setting reinforced these networks. Hence the synergistic effect of high pressure and MTGase can enhance the textural and functional properties of fish gels, when compared with the conventional cooking.