Currently, industry is requesting proven techniques that allow the use of encapsulated
polyphenols, rather than free molecules, to improve their stability and bioavailability. Response surface
methodology (RSM) was applied in this work to determine the optimal composition and operating
conditions for preparation of water-in-oil-in-water (W/O/W) emulsions loaded with phenolic rich
inner aqueous phase from olive mill wastewater. A rotor-stator mixer, an ultrasonic homogenizer
and a microfluidizer processor were tested in this study as high-energy emulsification methods.
Optimum results were obtained by means of microfluidizer with 148 MPa and seven cycles input
levels yielding droplets of 105.3 3.2 nm in average size and 0.233 0.020 of polydispersity
index. -potential, chemical and physical stability of the optimal W/O/W emulsion were also
evaluated after storage. No droplet size growth or changes in stability and -potential were observed.
Furthermore, a satisfactory level of phenolics retention (68.6%) and antioxidant activity (89.5%) after
35 days of storage at room temperature makes it suitable for application in the food industry.
