Abstract
There are various types of cosmetic emulsion. Emulsion is defined as a liquid dispersed in an immiscible liquid (such as water and oil). In this study, we focused on D phase emulsification method, which is categorized into a low-energy emulsification. In the D phase emulsification method, synthetic surfactants have been widely used because of its high emulsification capacity. However, natural surfactant tends to be preferred because cosmetics is directly applied to skin. The primary purpose of this study was to examine whether sodium surfactin, a natural surfactant, was feasible for preparation of emulsion using D phase emulsification method. Moreover, we attempted to improve stability of the emulsion by coating the droplets with hydrogel membrane. We showed that application of sodium surfactin for D phase emulsification resulted in successful preparation of emulsion with fine oil droplets in aqueous phase. We further attempted to coat the oil droplets with (i) sodium alginate membrane, (ii) propylene glycol alginate/chitosan complex membrane or (iii) propylene glycol alginate/glycol chitosan complex membrane. The droplets could be coated with membrane (ii) and (iii). Stability of emulsion of membrane (iii) was higher than that of membrane (ii).
