Interaction of starch nanoparticles with digestive enzymes and its effect on the release of polyphenols in simulated gastrointestinal fluids

This study investigates the interaction of amino-modified starch nanoparticles (NH₂-SNPs) and unmodified SNPs with pepsin and trypsin and the influence of the formation of protein coronas on the release of polyphenols. We discovered that NH₂-SNPs bound loosely to pepsin, while they bound tightly to trypsin, by quartz crystal microbalance with dissipation monitoring and zeta potential measurement. SNPs did not easily bind to the two digestive enzymes. In addition, the influence of NH₂-SNPs on digestive enzymes was investigated by ultraviolet-visible spectrophotometry, and circular dichroism spectroscopy, showing that the addition of NH₂-SNPs had no effect on the conformational structure of pepsin and trypsin. Using NH₂-SNPs and SNPs to load four polyphenols revealed that the nanoparticles had a slow-release effect on the polyphenols, but the presence of protein coronas had little effect on the release. The release was mainly related to the destruction of the starch-based carrier by the amylase in digestive enzymes.