Hydrophobic interaction-induced self-assembly of V-type lotus starch with butyric acid into stable structures: Regulation by butyric acid concentration.

Abstract

V-amylose is a modified helical structure capable of interacting with butyric acid (BA), which typically shows limited affinity for native amylose. The encapsulation of BA within V-amylose enhances its enzymatic resistance while facilitating the delivery of BA to the gut, where it can exert beneficial health effects. Consequently, enhancing the incorporation of BA into starch-based food is a crucial strategy for achieving these objectives. The concentration of guest BA plays a critical role in the hydrophobic interaction-induced complexation with V-amylose, and understanding the structural changes involved in this process is essential for the design of optimal products. In this study, V-amylose derived from high-amylose lotus starch was utilized to form complexes with BA. The structure and in vitro digestibility of the complexes formed at varying BA concentrations were investigated. The results demonstrate that higher BA concentrations weakened the hydrophobic interactions in the V-amylose system. Nevertheless, the highest complex index (i.e., 11.7 g/100 g) of V-amylose was attained at a 50 % BA concentration, indicating a balance between BA-regulated hydrophobic aggregation and the density of BA during complexation. These V-amylose complexes produced with elevated BA content exhibited high crystallinity and molecular order, along with enhanced thermal stability and resistance to enzymolysis. These findings support the feasibility of loading BA into V-amylose and provide valuable insights into the hydrophobic complexation regulated by BA concentration.