Amylose content controls the structures and digestibility of starch-lipid complexes during microwave postprocessing

Food postprocessing modifies the structures and properties of starch-lipid complexes, but the impact of amylose content on these changes remains unclear. In this work, starch-lipid complexes with different amylose contents (waxy corn starch: WC; normal corn starch: NC; Gelose 50: G50; and Gelose 80: G80) were prepared and the changes in structures and digestibility following microwave heat-moisture treatment (M-HMT) were investigated. Results indicated that M-HMT induced some destruction of helical structures of WC-lipid complexes, accompanied by reduced complexed lipid content, complex index, short-range molecular order, and relative crystallinity. However, for NC-lipid, G50-lipid, and G80-lipid complexes, these characteristic parameters were increased after treatment. Additionally, for the four types of treated complexes, higher amylose content led to higher values of these parameters. Notably, M-HMT endowed complexes with lower digestibility, and complexes with higher amylose content showed stronger enzyme digestion resistance. The treated G80-lipid complexes achieved the highest resistant starch content of 55.41 %. This work is expected to offer theoretical foundation and practical guidance for industrial or household production of starchy foods with a better health effect.