Comparative molecular conformation, interaction, and network characteristics of wheat gluten modulated by sodium chloride and sodium carbonate

Abstract

SummaryThe objective of the study was to investigate the configurational changes and aggregation mechanism of wheat gluten induced by sodium chloride (NaCl) and sodium carbonate (Na2CO3). The results showed that NaCl shielded surface charges of gluten, developed more hydrogen bonds with tyrosine, and stabilised the secondary structure, while Na2CO3 promoted significant transition of the secondary structure from random coils and β‐turn to β‐sheet. Both NaCl and Na2CO3 quenched tryptophan fluorescence and promoted the aggregation of gluten subunits, where Na2CO3 induced covalent bond formation other than disulphides and facilitated gluten network development. Atomic force microscopy images confirmed different molecular surface features in gluten network. In conclusion, both NaCl and Na2CO3 demonstrated the ability to promote rheology, aggregation, and network formation of gluten but different molecular mechanisms were involved. This work provides valuable insights for the processing of salted and alkaline noodles.