High hydrostatic pressure induced gastrointestinal digestion behaviors of quercetin-loaded casein delivery systems under different calcium concentration.

Casein micelle has a structure of outer hydrophilicity and inner hydrophobicity, its typical digestion characteristic is gastric coagulation. Based on calcium content as the key factor to control this process, high hydrostatic pressure (HHP) was firstly used to modify the micelle structure by mediating the tight connection between casein molecules themselves and with colloidal calcium, then the quercetin-loaded delivery systems were prepared. And in order to investigate the effect of exogenous calcium, calcium chloride was added for digestion. The results indicated that HHP broke the limitation of casein micelles as delivery carriers for hydrophobic components and increased the EE from 51.18 ± 3.07 % to 76.17 ± 3.41 %. During gastric digestion, higher pressure and exogenous calcium synergistically increased the clotting ability and inhibited the release of quercetin. In the small intestine, curds decomposed more slowly under higher pressure and calcium concentration, so the degradation of quercetin was effectively inhibited.