Changes in the molecular and structural of wheat gluten in the presence of zein during heating: Comparative studies on gluten, glutenin and gliadin

Abstract

This study comparatively investigated the heat-triggered molecular and structural changes of wheat gluten in the presence of zein to clarify the gluten and zein interaction mechanism from the perspective of gluten, glutenin, and gliadin polymerization behavior during heating. Scanning electron microscopy (SEM) images showed that zein induced more uniform dispersion of the gluten network during heating. Size exclusion-high performance liquid chromatography (SE-HPLC) results demonstrated that zein addition increased the SDS-soluble protein content in the gluten, glutenin, and gliadin during heating. After heating at 95 °C, zein increased the free sulfhydryl content in gluten and glutenin by 23.15% and 38.97%, respectively. Zein primarily enhanced the non-covalent interaction with gliadin more than with gluten and glutenin. The addition of zein led to a significant decrease in β-sheets content in gluten, glutenin, and gliadin during heating. Zein improved the thermal stability of gluten and gliadin after heating, resulting in higher degradation temperatures and lower weight loss. The improvement in rheological properties of gluten, glutenin, and gliadin during the 95 °C heating phase could be mainly attributed to the prevention of excessive protein aggregation and the promotion of non-covalent interactions by zein.