Starch nanoparticles regulate the steric conformation of soy protein isolate to stabilize high internal phase Pickering emulsions for curcumin encapsulation.

This study aimed to the fabrication of high internal phase Pickering emulsions (HIPEs) via regulating the complexation of starch nanoparticles (SNPs) with soy protein isolate (SPI) at the oil-water interface. The formation of SNPs-SPI complexes was driven by the electrostatic adsorption and hydrogen bond interactions, which enhanced the biphasic wettability and reduced the interfacial tension. The SNPs-SPI complexes exhibited the superior emulsifying properties compared to those of SPI, with the SNPs3-SPI achieving the highest emulsion activity index (EAI, 65.67 m/g) and emulsion stability index (ESI, 138.48 min). The rheological measurement revealed that the HIPEs stabilized by SNPs-SPI complexes (SNPs-SPI-E) exhibited the higher viscoelastic and gel-like structure than those of HIPEs stabilized by SPI (SPI-E). The adsorption of SNPs at the oil-water interface endowed the SNPs-SPI-E with higher encapsulation efficiency of curcumin (83.19 %-92.37 %) than that of SPI-E (75.42 %), which impeded the degradation and oxidation of curcumin. Moreover, the SNPs-SPI-E possessed the excellent storage and thermal stabilities than those of SPI-E. The curcumin encapsulated in SNPs-SPI-E exhibited the increased bioaccessibility, with SNPs3-SPI-E reaching the highest value of 38.92 %. This research would be beneficial to development of SNPs-SPI complexes interface for stabilizing HIPEs and modulating the encapsulation of bioactive ingredients.