Aggregation behavior of wheat gluten during carboxylic acid deamidation upon hydrothermal treatment

Changes of aggregation behavior of wheat gluten during carboxylic acid deamidation upon hydrothermal treatment were investigated to test the influences of deamidation on the aggregation extent of wheat gluten. Hydrothermal treatment induced that the size of soluble wheat gluten aggregate progressively increased by cross-linking of gliadins and slowly cleaved glutenins. But significant changes in molecular weight distribution, solubility under six denaturing agents’ treatment and Zeta potential of wheat gluten aggregates were observed at 6 min heating time and distinct shift of intra-/inter-molecular interactions of wheat gluten aggregates occurred before and after 6 min heating treatment respectively. Moreover, as heating time increased, the island-like aggregates decreased markedly and the striped aggregates increased notably. To explain the aggregation behavior in this case, we postulated that the extent of aggregation of wheat gluten depended on the balance between intra-/inter-molecular electrostatic repulsion, the non-covalent and disulfide bonds formation in the system. Hence, a scheme was drawn, which appeared to be the mechanism responsible for the aggregation of wheat gluten through thermal cross-linking and opening up of the network structure of wheat gluten aggregates by deamidation.

► Deamidation on the aggregation extent and shape of protein.
► Distinct shift occurred 6 min heating.
► Aggregation extent depends on the balance between electrostatic repulsion and aggregation forces.