Physicochemical properties and digestion mechanism of starch-linoleic acid complex induced by multi-frequency power ultrasound

[Display omitted] •Multi-frequency power ultrasound (MFPU) was used to form AS-LA inclusion complexes.•Physicochemical properties and in-vitro digestibility were modulated by MFPU.•Hydrogen bonds were major non-covalent linkages during AS-LA complex formation.•AS-LA complexes exhibited lower RDS, SDS, and higher RS contents as compared to control. The effects of multi-frequencies (mono: 20 kHz, 40 kHz, 60 kHz; dual: 20/40 kHz, 40/60 kHz, 20/60 kHz, and tri: 20/40/60 kHz) on physicochemical properties and in vitro digestibility of arrowhead starch-linoleic acid (AS-LA) complexes were evaluated. The complexing index and FTIR analyses showed that sonication treatment might be helpful in the formation of AS-LA complexes in an ultrasound frequency-dependent manner. The SEM micrographs revealed that the various ultrasonication frequencies caused dense network structure in AS-LA complexes. The XRD showed a V-type crystalline structure with increased crystallinity. Compared with arrowhead starch, a decrease in rapidly digestible starch , and an increase in resistant starch contents of AS-LA under various ultrasound frequencies was due to arrowhead starch and linoleic acid molecular interactions, which inhibited the further binding abilities. As a non-thermal technology, ultrasound could be effectively employed to prepare starch-lipid complexes with significant potential in functional foods and drug delivery systems.