Modulation of V-type starch structures using aqueous ethanol solutions of different polarities for controlled curcumin encapsulation and release

This study investigated the effect of different-polarity aqueous ethanol solutions on the formation of V -type starch originating from corn starch. Scanning electron microscopy revealed that the morphology of starch transformed from a random lamellar structure to a granular structure with decreasing solution polarity. When the ethanol concentration increased from 40 % to 60 %, the crystallinity and single-helix ratio of V -type starch increased from 9.66 % and 6.90 % to 29.77 % and 12.84 %, respectively. When the ethanol concentration was 100 %, the aforementioned parameters decreased to 21.31 % and 11.07 %, respectively. The crystallinity and curcumin encapsulation efficiency of the V -type starch reached their maximum values when this starch was prepared using 60 % aqueous ethanol. Furthermore, curcumin release experiments indicated that the produced starch–curcumin complex could resist gastric acid, and V -type starch with higher crystallinity exhibited a better sustained release effect in intestinal fluid. These results indicate that the formation of V -type starch can be finely regulated using aqueous ethanol solutions with different polarities, and such regulation is beneficial for the application of V -type starch in the oral delivery of guest molecules.