Influence of the span 80/Gelatin B combination on the formulation and stabilization of Argan oil-in-water emulsions

The present study aims to evaluate the effect of the combination of a linear protein: Gelatin type B and an oil-soluble emulsifier Span 80 (sorbitan monooleate) in the stabilization of argan oil-in-water emulsions. For this purpose, the emulsifiying properties of Gelatin itself with Argan oil as lipid phase were investigated first, by preparing oil-in-water (O/W) emulsions containing 10  wt%.  Argan oil and varying Gelatin concentrations (0.5-2 % w/w), we have also formulated Argan O/W emulsions by span 80 alone at levels ranging from 1 to 6 wt%. Subsequentely, we explored the influence of the simultaneous application of the Span 80 and the gelatine on the stability properties and on the droplets size of Argan O/W emulsions, using different mixtures of the two emulsifiers. We compared the stability properties (flocculation, creaming, and phase separation) of argan O/W emulsions prepared with type B gelatine as the only emulsifier with those of emulsions prepared with span 80 and mixture of gelatin/Span. For stable emulsions, our analysis was completed with measurement of droplets size and Zeta Potential. Finally, all of the experimental results and the storage time showed that the emulsions prepared by 10 wt% argan oil and 2 (w/w) % Gelatin+ 3 wt% Span 80 were the most stable with optimum conditions for minimal creaming, small droplets size (size <1µm) and high net droplet charge (absolute value of ZP > 23). The presence of span 80 in coexistence with gelatin, even in small quantitiees, has a profound influence on the stability of the argan O/W emulsions.