Fabrication and characterization of curcumin-encapsulated composite nanoparticles based on soybean protein isolate hydrolysate/soybean polysaccharides: Interaction mechanism, stability and controlled release properties

This study developed a stable nanoparticle (CUR-SPIH/SSPS) using soybean protein isolate hydrolysate (SPIH) and soybean polysaccharides (SPSS) to protect curcumin (CUR) from degradation during storage and exposure to light and heat conditions, achieving controlled release. The SPIH to SPSS mass ratio of 5:1 gave the CUR-SPIH/SPSS nanoparticles with the highest CUR encapsulation efficiency (95.60 ± 3.00 %) and the strongest antioxidant capacity (90.26 ± 2.42 % and 66.78 ± 1.89 % for ABTS •+ and DPPH radical scavenging ability, respectively), and CUR was successfully encapsulated within the CUR-SPIH/SPSS as evidenced by X-ray diffraction. FTIR and fluorescence spectroscopy analysis confirmed that the interactions in CUR-SPIH/SPSS are primarily driven by electrostatic, hydrogen bonding, and hydrophobic interactions. Moreover, the CUR-SPIH/SPSS nanoparticles significantly enhanced CUR's thermal and UV light stability. The UV degradation kinetics showed that the half-life of CUR-SPIH/SPSS (247.55 min) was 1.61 times longer than that of free CUR (154.03 min). The release rate of CUR incorporated into CUR-SPIH/SPSS was significantly delayed during in vitro gastrointestinal digestion. This study introduces an innovative nanoparticle strategy for the stable delivery of lipophilic compounds.