Encapsulation of curcumin in Pickering emulsions stabilized by hydrophobically modified rice starch: Octenyl (C8) versus dodecenyl (C12) succinic anhydride.

Esterified starch exhibits emulsifying properties and holds significant potential for application in the food and pharmaceutical industries. However, research on the influence of acid anhydride chain length on the physicochemical properties of starch and its capacity to encapsulate curcumin remains insufficient. In this study, two types of esterified starches, each with distinct hydrophobic chains, were synthesized: dodecenyl succinic anhydride starch (DDSAS) and octenyl succinic anhydride starch (OSAS). It was found that, in comparison to octenyl succinic anhydride (OSA), dodecenyl succinic anhydride (DDSA) led to a lower degree of substitution (DS) in the starch but imparted enhanced surface hydrophobicity to the starch (with a contact angle > 120°). With respect to emulsion morphology and storage stability, starches modified by OSA consistently produced more stable Pickering emulsions. Significantly, the emulsion stabilized with 5% octenyl succinic anhydride-modified starch (OSAS-5) exhibited outstanding performance, achieving an emulsification index of 64.8% and maintaining a curcumin retention rate of 67.7% after 7 d of storage. This study provides novel insights into the efficient encapsulation and controlled release of bioactive components in functional foods.