Investigation on the Molecular and Physicochemical Changes of Protein and Starch of Wheat Flour during Heating

Abstract

The behaviors of starch and protein in wheat flour during heating were investigated, and the molecular changes of starch and protein and their effects on the textural characteristics were assessed. The results showed that with the increased temperature, soluble protein aggregated to insoluble high-molecular-weight protein polymers when the heating temperature exceeded 70 °C, and the aggregation of protein was mainly caused by covalent bonds of disulfide (SS) bonds. Hydrophobic interaction was the main noncovalent bond that participated in the formation of protein aggregates. The major change in the secondary structure during heating was a pronounced transition towards β-sheet-like structures. Considerable disruption of ordered structures of starch occurred at 70 °C, and starch was fully gelatinized at 80 °C. Typical starch pasting profiles of cooked flour were observed when the temperature was below 70 °C, and heat treatment decreased the pasting viscosity of the cooked flour from control to 80 °C, whereas the viscosity of the wheat flour increased in heating treatment at 90, 95 and 100 °C. The intense protein-starch interaction during heating affected the textural characteristic of flour gelation, which showed higher strength at 90, 95 and 100 °C. This study may provide a basis for improving wheat flour processing conditions and could lead to the production of new wheat products.

Effect of High-Molecular Weight Glutenin Subunits (HMW-GSs) on Gluten Polymerization during Biscuit Making: Insights from Experimental and Molecular Dynamics Simulation Study

“…The change and specific role of gluten and HMW-GS during baking remained unclear. In this study, gluten polymerization was observed during biscuit baking, accompanied by the significant increase of the SDS-I level; this was evidently attributed to the heat-induced crosslinking reaction of protein during baking . Gluten polymerization is due to the oxidation of the free SH groups of cysteine and/or SH-SS interchange reactions.…”

“…In this study, gluten polymerization was observed during biscuit baking, accompanied by the significant increase of the SDS-I level; this was evidently attributed to the heat-induced crosslinking reaction of protein during baking. 31 Gluten polymerization is due to the oxidation of the free SH groups of cysteine and/or SH-SS interchange reactions. Free SH groups of cysteine on the peptide chain of glutenin and gliadin undergo oxidation reaction to from SS bonds, and the cysteine residues are converted into cystine residues, which refer to the free SH oxidation reaction.…”

Pretreatments and Particle Size on the Glycemic Index and Rheological and Functional Food Properties of Bean Flours

“…The upper rates of G ′ and G ′′ of SCD24_C reflect the formation of a more rigid structure compared to the untreated samples R, indicating molecular interactions and structural modifications caused by heat treatment, and that could form a high-density three-dimensional network of cross-linked proteins and starch when gelatinization occurs. Probably, the macroscopic expression was the consequence of microlevel changes of starch and protein [ 57 ].…”