Fabrication of small-sized starch nanoparticles and their inhibition of interfacial enzymatic hydrolysis of granular starch

Starch nanoparticles (sNPs) are promising for glycemic control and bioactive delivery, yet achieving high-yield, sustainable production of ultra-small particles (<50 nm) with clarified inhibitory mechanisms against digestive enzymes remains a significant challenge. This study systematically addressed this gap by developing a scalable, sustainable fabrication method for ss-sNPs. It further elucidates how nanoparticle size and amylose content influence their interfacial inhibitory mechanisms against glucoamylase (GA). We produced ss-sNPs with a high yield (90%) using an environmentally friendly approach combining enzymatic modification and sonication. The ss-sNPs measuring 10–30 nm, derived from branching enzyme-treated potato starches of varying amylose content, exhibited stability for one week before swelling to 84–833 nm during storage. Notably, the ss-sNPs exhibited enhanced resistance to in vitro digestion by glucoamylase (GA). While the ss-sNPs (10–14 nm) from high amylopectin (waxy, WPS) and normal (NPS) potato starch non-competitively inhibited GA hydrolysis of wheat starch granules, larger ss-sNPs (30 nm) from high amylose starch (HPS) un-competitively inhibited GA weakly, indicating GA-sNPs ternary complex formation with granular surfaces. Interfacial kinetics and Langmuir binding analyses further revealed loss of GA attack and binding sites. This scalable and sustainable ss-sNPs fabrication strategy offers remarkable interfacial capabilities unlocking potential applications in the food and biotechnology sectors.