A novel Pickering emulsion stabilized solely by n-butyric acid-modified high-amylose corn starch for resveratrol delivery

In this study, n-butyric acid-modified high-amylose corn starch (NBA-HACS) with varying degrees of substitution (DS ≈ 0.1, 0.2, 0.3) was synthesized via carbodiimide-mediated esterification and employed to fabricate Pickering emulsions for resveratrol encapsulation and delivery. Structural characterization confirmed successful grafting of n-butyric acid onto the C-6 hydroxyl groups of native high-amylose corn starch (NA-HACS), enhancing particle hydrophobicity. The contact angle increased from 24.6° (NA-HACS) to 86.3° (NBA-HACS), indicating a pronounced enhancement in particle dual wettability. NBA-HACS3 formed stable Pickering emulsions at 10% (w/v) concentration and oil-to-water ratios of 4:6 and 5:5, maintaining structural integrity across pH 1–11 and remaining stable after 90 days of storage. NBA-HACS3 achieved high resveratrol encapsulation efficiency (90.3%) and exhibited excellent retention under thermal (37 °C, 35 days) and UV conditions (11 h ). In vitro digestion studies revealed that NBA-HACS3 emulsions enhanced resveratrol bioaccessibility to 38%, five times higher than the control. This resulted from efficient interfacial encapsulation enabled by increased hydrophobicity, enhanced acid resistance preserving droplet integrity under gastric conditions, and improved micellar solubilization during intestinal digestion. This establishes an effective modification strategy for enhancing starch-based particle emulsifying performance, offering a promising food-grade delivery system for hydrophobic bioactives in functional food applications.