Abstract:

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 (0M and 0.6M NaCl) and pH 6.5. MTGase treatments in 0M NaCl solution decreased the size of myosin heavy chain through deamidation, but this was inhibited by GH or in 0.6M 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 0.6M NaCl, which was shown to result from reduced protein aggregation. However, GH improved (P<0.05) emulsifying properties of MPI, regardless of MTGase treatment.