Abstract: In this experiment, the effects of stirring rate and emulsifier type on the stability of W/O/W double emulsion were studied in order to optimize the process parameters. The ability of W/O/W double emulsion to encapsulate cyanidin-3- glucoside (C-3-G) was evaluated as well. The optimum conditions were found to be as follows: stirring rate 15 500 r/min for the first emulsification, 7 000 r/min for the second emulsification, polyglycerol ricinoleate concentration (PGPR, oil phase emulsifier) 16%, hydrophile lipophile balance (HLB) of hydrophilic emulsifier 10, and hydrophilic emulsifier concentration 10%. Under these conditions, the retention rate after centrifugation reached 80.25%. C-3-G was well encapsulated by the optimized multiple emulsion. It was found that the drug-loading rate of the emulsion was 1 500 mg/L and the encapsulation efficiency was 98.08%. The encapsulation of C-3-G improved the emulsion stability by increasing the viscosity of the inner water phase.

Key words: W/O/W emulsion, process optimization, cyanidin-3-glucoside (C-3-G), encapsulation