Spray dried double emulsions containing procyanidin-rich extracts produced by premix membrane emulsification: effect of interfacial composition.

Spray drying of procyanidin-loaded W1/O/W2 emulsions produced by premix membrane emulsification (ME) enabled to produce microcapsules containing procyanidins. The interface of the emulsion droplets prior to spray drying was stabilized with several hydrophilic emulsifiers (whey protein (WPI), WPI-carboxylmethyl cellulose, WPI-gum Arabic, and WPI-chitosan). Their effect on procyanidin encapsulation efficiency, water activity, moisture and oil content, and microcapsule size distribution was investigated. Furthermore, the microstructure and droplet size distribution of redispersed microcapsules were analyzed. Although premix ME produced W1/O/W2 emulsions with a narrow droplet size distribution regardless the hydrophilic emulsifier (main peak of droplet size distribution around 9 μm), microcapsules after spray drying and double emulsions after redispersion showed profound differences in sizes depending on the interfacial composition. WPI-CMC stabilized microcapsules not only showed the highest procyanidin content (5.3 g kg(-1)) but also gave the narrowest particle size distribution with the lowest particle size for both microcapsules and the corresponding emulsions after rehydration (7.7 and 9.9 μm respectively).