Encapsulation of Resveratrol Using Water-in-Oil-in-Water Double Emulsions

The suitability of water-in-oil-in-water multiple emulsions to encapsulate resveratrol was assessed. Multiple emulsions were prepared by emulsifying a primary emulsion (40 wt.%) in water containing 0.5 wt.% sodium caseinate and 0.1 M NaCl. Four primary emulsions of canola oil (20 wt.%) stabilized by 8 wt.% polyglycerol polyricinoleate were chosen. The dispersed phase of the primary emulsions contained 0.1 M NaCl and either water, 20 wt.% ethanol in water, 2.5 wt.% whey protein isolate (WPI) in water, or 2.5 wt.% WPI and 5 wt.% gelatine in water. Resveratrol was incorporated into these primary emulsions at 0.25 wt.% to give a final 0.02 wt.% resveratrol in the multiple emulsions. Slight increase in particle size with storage at 23 °C for up to 2 weeks was observed. Further, less than 10% of the total encapsulated resveratrol is released to the external, continuous, aqueous phase. This work demonstrates the potential of multiple emulsions to encapsulate resveratrol for food applications.