Abstract: This study was carried out in order to explore the effect of ultrasonic treatment at different temperatures (0, 20, 40 and 60 ℃) on the ability of maize starch to form a complex with lipid. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), X-ray diffractometry (XRD), laser confocal micro-Raman spectroscopy and were used to characterize the changes in the multilevel structure of maize starch granules before and after treatment, and the mechanism for the change in its lauric acid complexing capacity was analyzed. The results showed that the lipid complexing capacity of maize starch was significantly (P < 0.05) reduced by ultrasonic treatment, and the complexing index decreased from 27.9% to 15.0% with increasing temperature from 0 to 60 ℃; the enthalpy change (ΔH), relative crystallinity, degree of short-range order and relative content of resistant starch declined. Through the multi-level structure analysis, it was found that the molecular chain of the starch was depolymerized by ultrasonic treatment, and ultrasonic treatment at 60 ℃ caused the leaching of amylose from starch granules, thereby damaging their integrity and making the surface rough. In conclusion, ultrasonic treatment at different temperatures can reduce the lipid complexing capacity of starch by changing its multilevel structure.

Key words: ultrasonic treatment; maize starch; starch-lipid complex; multilevel structure; in vitro digestibility