Freezing-induced loss of wheat starch granule-associated proteins affected dough quality: From water distribution, rheological properties, microstructure, and gluten development

This study aimed to explore the effect of freezing/thawing (F/T) treatment on starch granule-associated proteins (SGAPs) and its mechanism for modifying dough quality. SDS-PAGE showed that F/T mainly induced a loss of proteins from the starch surface (SGSPs). It was found that the decrease in associated protein content increased the content of bound water from 27.04% and 18.94% to 32.40% and 27.78% in starch and reconstituted dough systems, respectively. The absence of SGSPs resulted in a rheological behavior with higher dynamic modulus and lower strain detected by frequency sweep and creep-recovery experiments. CLSM exhibited a local aggregation of the gluten network and more starch granules dissociated. The glutenin macropolymers (GMP) content increased from 76.45% to 83.31% while the values of fluorescence intensity and free sulfhydryl (SH) decreased to 2821 and 1.85 mu mol/g, respectively. These results suggested that SGSPs acted as a contact site in the "starch-gluten" matrix, facilitating macromolecular adhesion.