Effects of phenolic compounds from sorghum bran, grape seed and green tea on dough rheology and bread quality in reduced-salt formulations

This study investigated the effects of phenolic compounds (0.5 %–1.5 %) extracted from sumac sorghum bran (SBE), grape seed (GSE), green tea (GTE) on the quality of reduced-salt bread (0.8 % salt). To understand the mechanisms underlying these effects, the influence of SBE, GSE, and GTE on dough mixing properties, extensional properties and gluten surface hydrophobicity were characterized. SDS-PAGE analysis was employed to examine protein cross-linking and interactions between phenolics and gluten. The results showed that phenolics primarily interacted with gluten through hydrogen bonding and hydrophobic interactions. Specifically, these compounds exhibited preferential binding to high-molecular- weight proteins in glutenin macropolymers (GMP). The addition of 0.5 %–1.0 % SBE and 0.5 % GSE significantly enhanced dough strength while maintaining bread quality comparable to the 1.5 % salt control. In contrast, increasing GSE to 1 % caused excessive dough strengthening, adversely impacting bread quality. Furthermore, when GSE concentration reached 1.5 %, the dough strength significantly decreased (P < 0.05), attributable to excessive phenolic compound interactions, ultimately resulting in diminished bread quality. Adding GTE reduced dough strength and bread quality, likely due to its high total phenolic content and antioxidant properties. In conclusion, SBE and GSE show potential as partial salt replacers in bread formulations, offering a viable approach to reducing salt content while maintaining dough and bread quality. • SBE and GSE enhanced gluten functionality and the quality of low-salt bread. • GTE reduced the dough strength and quality of bread. • Phenolic compounds interacted with gluten mainly via hydrogen bonds. • Phenolic compounds exhibited a preference for interacting with HMW-GS.