Comparative Study and Performance Evaluation of Chemical and Biosurfactants in Water-in-Oil Emulsification Process

Surfactants are used to lower the interfacial tension by adsorption process at the interface between oil and water. Chemical surfactants pose detrimental effects to equipment used and the environment as it consists of toxic compound. Environmentally friendly surfactant such as biosurfactant nowadays is the most sought after as perceived to be biodegradable, less toxic, high selectivity and biocompatible over chemical surfactant. In this study, stability of water-in-oil emulsion was observed using A-MeG (chemical surfactant) and Hylocereus undatus foliage (biosurfactant) at varying concentrations (samples A, B, C) via several measurement methods namely; droplet size, surface tension, rheology and creaming index. Results revealed that sample A with A-MeG and sample C with Hylocereus undatus foliage had smaller droplet sizes at 7.844 μm and 8.032 μm, respectively; lower average interfacial tension at 29.0 mN/m and 29.2 mN/m, respectively; higher average viscosity at 0.004061 mPa.s and 0.004171 mPa.s, respectively; which indicated that both were the most stable emulsion samples. Sample A with A-MeG had high creaming index, however, no water separation was recorded. While, sample C with Hylocereus undatus foliage recorded lower creaming index which indicated high stability. In conclusion, it is proven that there is a possibility of using Hylocereus undatus foliage in stabilising the water-in-oil emulsion.