Preparation of monodisperse O/W emulsions using a crude surface-active extract from argan by-products in microchannel emulsification

Abstract

In this study, we evaluated the performance of a mildly derived extract from argan by-products in microchannel emulsification (MCE). Our aim is to produce stable monodisperse O/W emulsions using this extract as a sole emulsifier. Preliminary investigations about the characteristics of argan extract indicated the potential interaction between surface-active components (i.e. saponins, proteins), in bulk phase prior to adsorption at the oil/water interface, resulting in the formation of biogenic complexes with strong interfacial properties. This is important for successful MCE as this technique depends exclusively on dynamic interfacial tension reduction for droplet formation. Nevertheless, upon performance of emulsification experiments, we also found that the complex composition of this extract could counteract its emulsifying efficiency, by creating a hydrophobic, or slightly hydrophilic, layer on the MC array plate surface. This resulted in unsuccessful emulsification using short MCs but did not affect the emulsification behavior in longer ones. Using longer MCs, we could produce stable monodisperse O/W emulsions, with similar droplet size (∼ 36 μm) and droplet size distribution (Relative span factor <0.25) to those obtained using Tween 80, and for up to 10 h of continuous emulsification.

Keywords: Argan by-products; crude emulsifying extract; monodisperse emulsion; microchannel emulsification.