Abstract:In this study, Chinese yam starch-lauric acid complexes were fabricated via three ultrasonic strategies: pre-ultrasonic treatment, simultaneous ultrasonic treatment and post-ultrasonic treatment, to investigate the effects of different ultrasonic modes on the physicochemical properties of the complexes. The results revealed that all three ultrasonic treatments destroyed the ordered crystalline structure of starch through physical cavitation and shearing effects, and induced the formation of V-type hydrophobic complexes between amylose and lauric acid, with distinct modification performances observed among groups. Pre-ultrasonic and post-ultrasonic treatments improved the retrogradation and sedimentation properties of complexes, yet inhibited the dissolution and swelling capacity of starch under high temperature. Simultaneous ultrasonic treatment continuously loosened the starch skeleton, achieving a complex index of 76.55 %, and endowed samples with desirable properties including low oil absorption, high water absorption, strong dissolution and swelling capacity. All ultrasonic treatments reduced the transparency of complex pastes. FTIR and XRD characterizations verified that ultrasound merely strengthened intermolecular hydrogen bonds and hydrophobic interactions via physical approaches without altering the non-covalent complexation mechanism. The simultaneous ultrasonic group exhibited the lowest relative crystallinity of 8.71%. In conclusion, targeted regulation of functional properties of starch-lauric acid complexes can be realized by adopting different ultrasonic treatments, which provides theoretical support for the high-value processing of Chinese yam starch.