Correlation between multi-scale structure and log-of-slope digestive kinetics of a novel slowly digestible starch:...

Chempedak seeds are abandoned as a by-product, resulting in wasting starches, proteins, and lipids. Accordingly, the present research investigated the log-of-slope digestive kinetics of chempedak seed amylopectin (CPSS')-lauric acid (LA)-β-lactoglobulin (βLG) complex. Compared to that of CPSS', CPSS'-LA-βLG complex amylopectin long chain was reduced, complexing index was 52.11 %, and crystalline structure exhibited Type-V + B. These results indicated that the enzymatic sites locating in the amylopectin long chain were encapsulated after complexation, thus, significantly increasing slowly digestible starch (SDS) content (40.23 %) in CPSS'-LA-βLG complex compared to that in CPSS' (20.32 %). Moreover, CPSS'-LA-βLG complex exhibited increased relative crystallinity, semicrystalline orderliness, lamella thickness, and molecular mass but reduced crystallite unit length. This led to a compact and smooth morphology compared with that of chempedak seed starch (CPSS)-LA-βLG complex. Based on chemometric analysis, these factors led to higher SDS content, lower initial (2.23 × 10^-2 min^-1) and final digestion rate constants (1.43 × 10^-2 min^-1), and lower estimated glycemic index (81.07) in CPSS'-LA-βLG complex than in CPSS-LA-βLG complex (4.95 × 10^-2 min^-1, 1.99 × 10^-2 min^-1, and 84.14). It was also found that the different complexing sites and strong forces strong forces including hydrogen bonding, hydrophobic interactions, electrostatic attractions, and van der Waals enhance CPSS'-LA-βLG complex enzyme resistance compared to that in maize, cassava and potato starch complex. Therefore, CPSS'-LA-βLG complex could be considered as a well source to make foods for relieving the type II diabetes or hyperlipemia.