Improvement of stability of blueberry anthocyanins by carboxymethyl starch/xanthan gum combinations microencapsulation

The study was to improve the stability of blueberry anthocyanins (ANS) by encapsulating it with carboxymethyl starch (CMS)/xanthan gum (XG) combinations of five ratios (CMS/XG: 30/1, 60/1, 90/1, 120/1, 150/1, w/w). The results revealed that all the microcapsules presented high encapsulation efficiency. Fluorescence microscopy showed that ANS distributed homogenously through CMS/XG combinations, and the microcapsules revealed red-purple color. Thermogravimetric analysis (TGA) demonstrated that CMS/XG combinations working as wall materials increased the thermal stability of ANS. The cross-linking interactions between the CMS/XG combinations and ANS were confirmed by FTIR and C-13 solid-state NMR. Microcapsules created with an CMS/XG ratio of 30/1 provided superior antioxidant stability. Furthermore, the storage stability results showed that the stability of ANS was increased to 76.11% after the 30-day storage (37 degrees C) through CMS/XG. The in vitro release experiments revealed that the ANS were majorly retained inside CMS/XG-ANS microcapsules in the stomach, and released in the intestine. CMS/XG combinations microencapsulation can be a suitable method for stabilizing blueberry anthocyanins.