The stability of mulberry-extracted anthocyanin is a main concern in food supplement application. In this article, the alginate/chitosan beads were fabricated by spray drying and external gelation techniques using different processes: (1) dropping a sodium alginate solution into a CaCl2 solution containing chitosan and (2) incubating calcium alginate beads in a solution of chitosan. These beads were introduced as microcarrier to enhance the stability and bioavailability of anthocyanin. We showed that the beads fabricated by different processes could encapsulate the anthocyanin at different amounts. All alginate/chitosan beads had high swelling percentage under pH 6 and 7.4 but not completely swell at pH 1 and 4. The alginate/chitosan beads degraded in a simulated gastric fluid condition (SGF) in the faster rate than that in a simulated intestinal fluid condition (SIF). Under SGF condition, the release of anthocyanin seemed to be governed by electrostatic interaction while the release of anthocyanin under SIF condition may be manipulated by the beads' degradation. Herein, we showed that the beads produced by incubating calcium alginate beads in 0.05% chitosan solution were the most appropriate microcarriers for encapsulation of mulberry-extracted anthocyanin which showed high encapsulation efficiency and had resistance to gastric condition.
Keywords: Alginate; anthocyanin; chitosan; controlled release; encapsulation; microcarrier.