Complexation between burdock holocellulose nanocrystals and corn starch: gelatinization properties, microstructure, and digestibility in vitro .

Holocellulose nanocrystals ( h CNCs), with hydrodynamic diameters ( D Z ) ranging from about 600 to 200 nm, were prepared by treating burdock insoluble dietary fiber (IDF) with enzymes and ultrasonic power. It was revealed that h CNCs improved the viscosity of corn starch (CS) during pasting and inhibited its short-term retrogradation. Besides, the crystallinity, short-range order of the double helix, viscoelastic properties, and microstructure compactness of CS gels improved remarkably in the presence of burdock h CNCs. These effects were both size- and dose-dependent, which primarily originated from the hydrogen bonding between h CNCs and amylopectin or leached amylose. In this regard, the digestion of CS gels containing h CNCs was remarkably retarded because of the reduced accessibility of digestive enzymes to the glycosidic bonds. Therefore, burdock h CNCs, prepared from natural resources using green techniques, hold potential applications in functional foods of a low glycemic index.