Complexation of V-type lotus seed starch and butyric acid: Structure and in vitro digestion

Butyric acid (BA), a short-chain fatty acid, significantly impacts gut health but is rarely incorporated as a guest molecule in starch-based products. Owing to their hydrophobic helical cavities, V-type starches can form inclusion complexes (ICs) with BA via hydrophobic interactions. In the current work, V-type lotus seed starches (VLS) were used in complexation with BA, and the structure and in vitro digestion of V-type lotus seed starchbutyric acid complexes (VLS-BAcs) as influenced by preultrasonication were investigated. The results showed that at the suitable ultrasonic power (similar to 360 W), 28.4% of the additional BA was complexed with preformed VLS. The IC formation significantly increased the crystallinity of starches and retarded amylose retrogradation. Highly crystallized VLS-BAcs exhibited strong thermal stability and hydrophobicity and displayed bound waterdominated structures. Moreover, VLS-BAcs formed at 360 W had a 12.4% higher RS proportion than their untreated counterparts. These obtained findings would provide valuable knowledge on the properties of VLS-BAcs modulated by ultrasound pretreatment and reveal its potential as a novel prebiotic for increasing BA concentration in the gut.