Agriculture Sciences and Farming Technology

Biography

Biography: Zhenxin Gu

Abstract

Gluten deterioration is  main factor for the degraded quality of frozen dough. Previous studies comprehensively elucidated the degradation mechanism of gluten during frozen storage, however, the subsequent polymerization process of frozen-stored gluten remains largely unelucidated. Current study comparatively investigated effects of heating on the unfolding and polymerization process of fresh and frozen-stored gluten from molecular weight, subunit composition, non-covalent interactions, secondary structure, surface hydrophobicity and microstructure. The combined results of size-exclusion and reversed-phase high performance liquid charomatography showed that frozen storage degraded the polymerization of gluten during heating by weakening the polymerization ability of both gliadin and glutenin. Glutenin monomers were more sensitive, while the γ-gliadins were less sensitive to polymerize upon heating for frozen gluten. The sensitivities of glutenin polymers and the other gliadin subunits to the heating temperature were marginally affected by frozen storage. Frozen storage could impede the unfolding process at the initial heating stage for frozen gluten: fourier transform infrared spectroscopy analysis suggested that the ordered α-helices in frozen gluten were significantly higher than that of fresh gluten during heat treatment, and the surface hydrophobic groups tracked by the fluorospectrophotometer were more buried than fresh gluten. The scanning electron microscopy analysis suggested that the ruptured frozen gluten network was more sensitive to shrink during the initial heating at 50 °C and further formed denser and thicker pore walls when the temperature exceeded 70 °C. This study may provide a more comprehensive theoretical basis and technical support for the effective preservation of frozen dough quality.