Encapsulation of a bioactive peptide in a formulation of W1/O/W2-type double emulsions: Formation and stability

Abstract

The objective of this study is to formulate stable double emulsions of the water in oil in water (W1/O/W2) type containing a bioactive peptide (BP). The effects of the following parameters were investigated: the mechanical emulsification devices (high-speed homogenizer (HSH) ultrasonicator (US), microfluidizer (MF), and combinations of HSH with US or MF), the BP concentration (0–20 %), and the hydrophilic emulsifiers (Tween 80, chitosan, and a mixture of Tween 80 and chitosan) for the external aqueous phase on the droplet storage stability of double emulsions. The double emulsions with the optimum formation showed small droplet size, high encapsulation efficiency and good storage stability when 5% BP loading and the combination of high-speed homogenizer and microfluidizer was applied. Moreover, double emulsions stabilized by emulsifier-Tween 80 layers displayed excellent physical stability without phase separation. The double emulsions stabilized by an emulsifier-chitosan layer contained positively charged droplets and a thick layer in the external aqueous phase. However, double emulsion stabilized by the mixture of Tween 80 and chitosan emulsifiers showed a bi-modal size distribution, indicating that a synergistic interaction did not exist between Tween 80 and chitosan. The information obtained from this study is useful for preparing stable functional food or cosmetic products from double emulsions using a BP.