Formulation and characterization of nanoemulsion containing anthocyanin extract from purple yam (Dioscorea alata L.)

Anthocyanin is abundantly present in purple yam (Dioscorea alata L.) but it has instability and poor solubility in lipophilic system To overcome the challenges, a water-in-oil (W/O) based carrier system is needed to increase its solubility before being applied to food. Therefore, this study aimed to develop a stable W/O nanoemulsion formulation as a carrier for anthocyanin. The results showed that formula with a surfactant:water ratio of 5:1 was selected due to its low particle size and polydispersity index of 22.38 +/- 0.86 nm and 0.31 +/- 0.07, respectively. In addition, replacing 50% of water with anthocyanin produced a relatively stable anthocyanin with the lowest particle size of 18.31 +/- 6.52 nm. The findings also showed that antioxidant activity tended not to differ significantly and had higher retention compared to extract solutions with concentrated anthocyanin. These results indicated that nanoemulsion could protect anthocyanins and had the potential to be used in the food and health industry.