Effect of recombinant buckwheat trypsin inhibitor on gel properties of chicken meat emulsion

Summary The aim of this study was to investigate the effects of purified recombinant buckwheat trypsin inhibitor (rBTI) on gelling properties of chicken meat emulsion. Recombinant BTI was obtained by culturing and inducing an M15 strain containing pQE30‐BTI plasmid, and then purified by Ni 2+ affinity chromatography. rBTI exhibited good thermal stability and retained 67.7% ± 4.0% of its initial activity even after heating in a boiling water bath for 100 min. Results showed that the breaking force, deformation, penetration force and water‐holding capacity of chicken meat gels increased with the increase of rBTI (0‰–0.10‰), indicating that rBTI could improve the gel‐forming ability of chicken meat. Meanwhile, trichloroacetic acid (TCA)‐soluble peptide content decreased with rBTI addition and more myosin heavy chain (MHC) was retained on SDS‐PAGE. Compared with the group without rBTI, the content of TCA‐soluble peptide in the group with rBTI (0.10‰) decreased by 52.4%. rBTI is a specific inhibitor for trypsin, one of the dominant proteases resulting in myosin degradation. Thus, we concluded that rBTI improved the gel properties by deducing the degradation of myosin by endogenous enzymes. Furthermore, the addition of rBTI had no significant influence on the whiteness of the gels. With the advantages of good thermal stability, no unpleasant smell and the function of improving gel properties of meat emulsion, rBTI could be used as a potential candidate for food additives in food processing.