Structural, physicochemical and long-term retrogradation properties of wheat starch treated using transglucosidase

Abstract

To reduce the wheat-flour-based food texture and flavor deterioration caused by starch retrogradation, herein wheat starch, the most ingredient in wheat flour, was modified by transglucosidase to delay long-term retrogradation of wheat starch. The study proposed promising data of transglucosidase-treated starch about structure, crystallinity and retrogradation kinetics. Structural properties showed that transglucosidase treatment shortened the average chain length from 19.49 to 16.10 and induced the dominance of amorphous state. Moreover, branching degree increased from 14.11% to 17.97% after transglucosidase treatment, resulting in higher water mobility. Amylose content increased from 25.33% to 59.00% due to the hydrolysis ability of transglucosidase. Relative crystallinity of the retrograded starches decreased from 24.33% to 14.50%. Furthermore, the Avrami parameters demonstrated that transglucosidase treatment significantly retarded the retrogradation rate of wheat starch due to the decrease of re-crystalline rate. The outcoming would supply a solid theory foundation for exploring the wheat staple foods with higher qualities.

Keywords: Retrogradation properties; Transglucosidase; Wheat starch.