Microencapsulation of anthocyanins through two-step emulsification and release characteristics during in vitro digestion.

An anthocyanin-rich double emulsion (w/o/w) was prepared via a two-step emulsification method. Anthocyanins from black rice extract were incorporated in the inner water phase and dispersed inside the middle oil phase, which was then dispersed into the outer water phase. Generation of the double emulsion was confirmed by optical microscopic analysis and its microencapsulation efficiency was 99.45 ± 0.24%. An in vitro digestion study was carried out to evaluate anthocyanin concentration changes and release characteristics of the double emulsion using simulated gastrointestinal fluids. After 2 h incubation in the simulated gastric fluid, the percentage of diffused anthocyanins was 3.66 ± 2.32%. These observations indicate that the double emulsion could control the release of anthocyanins in the stomach. During incubation in the simulated intestinal fluid, a total release of anthocyanins in the double emulsion was observed within the first 20 min. A pH-dependent degradation of anthocyanins was also evident.