A procyanidin-rich extract encapsulated in water-in-oil-in-water emulsions produced by premix membrane emulsification

• Multi-layered double emulsions can be produced by premix membrane emulsification.
• Premix membrane emulsification can produce procyanidin-loaded double emulsions.
• Double emulsion stability depended on each type of interfacial multi-layer.
• Release of procyanidins from the double emulsion was diffusion controlled.
• Thicker WPI—polysaccharide layers lead to lower procyanidin release rate constants.

Premix Membrane Emulsification (ME) enabled us to produce procyanidin-loaded W1/O/W2 emulsions with narrow droplet size distributions. The emulsion interface of the outer droplets were stabilized with several hydrophilic emulsifiers (whey protein (WPI), WPI–Carboxymethyl cellulose, WPI–Gum Arabic, and WPI–Chitosan) and their effect on procyanidin encapsulation, droplet stabilization, and creaming stability in different pH environments was determined.Although premix ME produced emulsions with a narrow droplet size distribution for all hydrophilic emulsifiers with sizes around 10 μm, droplet coalescence was observed at high (pH 7) or low pH (pH 3) environments depending on the hydrophilic emulsifier. A certain range of pH was found for each hydrophilic emulsifier at which double emulsions were stable up to 14 days. The procyanidin release of W1/O/W2 emulsions stabilized with the several WPI–polysaccharides was measured during 14 days and depended on the interfacial thickness of the adsorbed hydrophilic emulsifier. WPI–Chi stabilized W1/O/W2 emulsions showed the highest stability in droplet size distribution and the lowest procyanidin release at a narrow pH range. A thicker interfacial WPI–Chi layer (4.2 nm versus 2.2 and 3.9 nm for WPI–CMC and WPI–GA, respectively) resulted in a lower procyanidin release.

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