Quinoa protein isolate-gum Arabic coacervates cross-linked with sodium tripolyphosphate: Characterization, environmental stability, and Sichuan pepper essential oil microencapsulation

Quinoa protein isolate-gum Arabic coacervates (QPI-GA coacervates) was cross-linked with sodium tripolyphosphate (STPP) to enhance their physicochemical properties. The optimum concentration of STPP for cross-linking was determined experimentally to be 0.2 g/g of QPI-GA mixture. After cross-linking, QPI-GA coacervates changed to the more ordered structure, and showed higher pH, ionic, and thermal stability. The STPP cross-linked coacervates were used as wall materials for Sichuan pepper essential oil (SPEO) encapsulation with encapsulation efficiency of 87.25 %. Compared with uncross-linked microcapsules, cross-linked microcapsules showed higher SPEO retention at high temperature, different pH, and high ionic concentration. Meanwhile, STPP cross-linked microcapsules improved the stability of SPEO during oral and gastric digestion as indicated by the lower SPEO release, which guaranteed the higher release and absorption in intestinal digestion of SPEO. Consequently, STPP cross-linked QPI-GA coacervates can be an ideal carrier for flavors or active ingredients, protecting them against harsh environment conditions during food processing and digestion.