Stability and bioactivities of Mesona chiensis Benth extract microbeads under simulated gastrointestinal digestion

Abstract

Alginate-calcium microencapsulation of Mesona chinensis extract (MCE) was conducted in this study. Firstly, the MCE was encapsulated by using calcium chloride (3 and 5% w/v) and sodium alginate (1.5 and 1.8% w/v) to form MC microbeads (MCB). The MCB with condition of 1.5% w/v sodium alginate, 3% w/v calcium chloride and 75% w/v MCE demonstrated the highest %encapsulation efficiency and suitable spherical shape among other conditions. According to Fourier-transform infrared spectroscopy (FT-IR), there was no strong chemical interaction between alginate and MCE. After simulated digestion, the total phenolic content (TPC) and antioxidant activity measured by ferric reducing antioxidant power (FRAP) of MCE was significantly decreased for 20.87 ± 3.78% and 41.95 ± 3.68% respectively. In gastric phase, alginate-encapsulation of MCE slow released the TPC and exhibited low FRAP value whereas it enhanced the release of TPC release and an increase in FRAP value in intestinal phase. The simulated gastric digestion of agar and carrageenan contained MC polyphenols, MCE and MCB, showed partially protection (~50%) and increased the gradual release of polyphenols after entering into the intestinal phase. The FRAP value of MC polyphenols in agar demonstrated the synergistic antioxidant activity. In conclusion, alginate encapsulation or incorporation in agar and carrageenan improve bioassessibility of MC polyphenols and its antioxidant activity.