Effects of thermal treatment on the physicochemical and structural properties of wheat gluten proteins: insights from gluten, glutenin, and gliadin fractions

This study examined changes in heat-induced gluten proteins, focusing on their structure, physicochemical properties, and molecular analysis. The results demonstrated that gliadin had a high denaturation temperature (68.04 degrees C) and minimal aggregation during heating (25 degrees C-95 degrees C), yet it hindered thermal reaction progress of gluten effectively. Heating caused a shift from alpha-helical structure to random coil and beta-turn structures, with a decrease in fluorescence intensity. High temperature reduced sulphydryl groups in gluten and glutenin, reaching 0.64 and 0.58 mmol L-1, respectively. However, the content of sulphydryl groups in gliadin remained relatively stable at around 0.37 mmol L-1. Notably, the configuration of disulphide bonds in gliadin, particularly in the g-g-g configuration, displayed greater stability. Microstructure analysis revealed increased compactness in all protein fractions as temperature rose. Overall, gliadin had greater thermal stability, impeding glutenin aggregation and gluten network formation. These findings provide valuable insights for cooking, processing, and storage of gluten proteins. Changes in the structural properties of gluten, glutenin, and gliadin under heat treatment. image