Construction of gelatin-based rutin delivery systems by ultrasound/pH-shifting pretreatment and polysaccharide modulation.

This study investigated the effects of polysaccharide types (chitosan oligosaccharide (COS), dextran, and soybean soluble polysaccharide (SSPS)) and ultrasound intensity (0, 300, and 500 W) on rutin-loaded gelatin nanoparticles prepared by pH-shifting. Ultrasound-assisted pH-shifting modified gelatin conformation, promoting polysaccharide binding and improving encapsulation and delivery. The results indicate that the sample modified with 500 W ultrasonication combined with pH 12.0 shift and SSPS (U500GS) exhibited optimal performance (p < 0.05), including the smallest particle size, the highest encapsulation efficiency, and the best stability, which may be possibly attributed to the steric hindrance of the SSPS network. In vitro digestion showed that U500GS reduced the burst release of rutin, enhanced bioaccessibility (89.71%, p < 0.05), and exhibited the strongest antioxidant activity (DPPH: 91.23%; ABTS: 86.43%; p < 0.05) and the highest protease hydrolysis resistance (hydrolysis degree: 53.28%; p < 0.05). This work reveals the roles of protein pretreatment and polysaccharide binding in delivery systems, offering a strategy for hydrophobic polyphenol utilization.