Revealing the impact of short side-chain migration on the digestive kinetics and multiscale structure of ultrasound-treated nano-scale amylopectin endogenous ternary complexes

Amylopectin complexes, as innovative dietary supplements, have significant potential in modulating rapid increases in the glycemic index. However, the mechanisms governing its anti-digestibility remain largely unknown. Therefore, this study investigated the effects of short side-chain migration on the anti-digestibility of white waxy maize amylopectin (WMS) complexes. WMS paste exhibiting different short side-chain migration rates were obtained using 4-α-glucotransferase and amylosucrase, and used to prepare nano-scale WMS complexes through an ultrasound-assisted process. Self-assembly capacity of amylopectin chains with protein and lipid groups was evaluated using a complexing index. Compared to the WMS paste, the nano-scale WMS ternary complexes transitioned from a diffuse pattern to a V-type crystalline type. This caused significant resistance of the WMS complexes to digestive enzymes compared to that of the WMS paste. Furthermore, increasing short side-chain migration rates of nano-scale WMS complexes increased the complexing index, short-range order, molecular conformation index, molar mass, molecular density, average characteristic size of crystallite unit, gelatinization temperature, potential, and resistant starch (RS-V), while reducing semicrystalline lamellae thickness, radius of gyration, size of particle surface nano nodule (blocklet), particle size, slowly and rapidly digestible starch, digestive speed rate from slowly digestible starch phase to RS-V phase, and expected glycemic index. Based on chemometric analyses, for short side-chain migration, the complexes showed greater accessibility of side chain sites to ligand residues, strengthened noncovalent interactions, and accelerated spherulite nucleation. This increased molecular homogeneity and density led to increased anti-digestibility. Collectively, these findings provide a novel theoretical framework for designing amylopectin-based multicomponent anti-digestible foods.