Hydrolyzed wheat gluten suppresses transglutaminase-mediated gelation but improves emulsification of pork myofibrillar protein

The influence of 15-h chymotrypsin-hydrolyzed wheat gluten (GH) on microbial transglutaminase (MTGase)-mediated interaction, gelation and emulsification of pork myofibrillar protein isolate (MPI) was investigated at two ionic strengths (0 M and 0.6 M NaCl) and pH 6.5. MTGase treatments in 0 M NaCl solution decreased the size of myosin heavy chain through deamidation, but this was inhibited by GH or in 0.6 M NaCl where myosin polymerization dominated. Stabilization of MPI (thermal transitions) by the MTGase treatment was also diminished (P < 0.05) by the presence of GH at both ionic strengths. These GH-induced MPI physicochemical changes greatly weakened the ability of MTGase to promote MPI thermal gelation (gel storage modulus, P < 0.05), especially at 0.6 M NaCl, which was shown to result from reduced protein aggregation. However, GH improved (P < 0.05) emulsifying properties of MPI, regardless of MTGase treatment.