Changes in structure, digestion, and curcumin release properties of starch constructed by protein fibrils-OSA starch interactions.

The influence of whey protein isolate fibrils (WPIF) on digestibility and release properties of octenyl succinic anhydride (OSA)-modified high amylose corn starch (OSA-HAS) was investigated in the aspects of WPIF-OSA-HAS interactions. Results showed that WPIF addition increased resistant starch content (31.52-42.85%) and encapsulation efficiency of curcumin (43.14-51.13%), whilst decreasing relative crystallinity and values of 1047 cm-1/1022 cm-1 ratio, achieving through hydrophobic interaction with OSA-HAS. The enzymatic resistance of WPIF-OSA-HAS complexes with different WPIF/OSA-HAS ratios followed the sequence of r = 0.10 < r = 0.20 < r = 0.30 < r = 0.50 < r = 0.40, and the release rates of curcumin occurred in opposite sequence. Notably, WPIF-OSA-HAS interactions depended on WPIF/OSA-HAS ratios, with the strongest for WPIF/OSA-HAS ratio of 0.4. These findings provided the first insight into the mechanisms behind the resistance of WPIF-OSA-HAS complexes to enzymatic digestion, and the potential for development of resistant starch-based carrier.