Effects of cyclodextrin glycosyltransferase on physicochemical, digestion, and gel properties of corn and potato starches

Abstract

The application of natural starches in the food industry is sometimes limited because of their high viscosity, strong susceptibility to retrogradation, and poor water retention capacity. In this study, cyclodextrin glycosyltransferase (CGTase) was used to modify corn starch (CS) and potato starch (PS) to investigate their physicochemical, digestion and gel properties. Rapid Visco-Analyzer (RVA) was used to determine the impact of this enzyme treatment on the gelatinization and retrogradation behavior of these two starches. The CGTase treatment reduced the viscosity and inhibited the short-term retrogradation of both starches. Enzymatic modification weakened the gel structure of corn starch but enhanced the gel structure of potato starch. The microstructure confirmed the above conclusion. The gel wall of CS became thinner, but more and smaller grids were generated, and the water holding capacity was enhanced after enzyme treatment, while the wall thickness of PS was not significantly changed, and the water holding capacity was relatively good on the whole. Compared with native starch, the enzyme modified starch exhibited a similar digestibility but the content of rapidly digestible starch was slightly higher. The crystal structure of starches was disrupted by the enzyme treatment, but that the covalent bonds within starches were not affected. Starch gels formed by CGTase treatment could be successfully used as edible inks in 3D food printing applications, which may be useful for the creation of personalized foods.