Abstract:Changes in the rheological behavior and thermal properties of wheat gluten after trypsin-based enzymatic hydrolysis and the subsequent transglutaminase (TGase) catalyzed cross-linking reactions were investigated and the structure of wheat gluten was characterized. The results indicate that an appropriate degree of trypsin-based partial enzymatic hydrolysis favored TGase cross-linking. The most significant composite modification effect was observed when 80 U/g trypsin-based partial hydrolysis was combined with TGase cross-linking, where the wheat gluten storage modulus (G’) and thermal denaturation temperature (Tg) increased from 2.26 kPa and 55.59°C to 6.46 kPa and 59.17°C, respectively. Structural analysis indicated that an appropriate degree of trypsin-based enzymatic hydrolysis could result in breakage of intermolecular disulfide bonds and an increase in surface hydrophobicity. Consequently, the compact wheat gluten structure became loose and more glutamine residues were exposed to allow TGase cross-linking. This resulted in the formation of a more compact and porous wheat gluten network structure from the hydrated wheat gluten. However, excessive enzymatic hydrolysis was unsuitable for TGase cross-linking.
