Development and physico-chemical characterization of virgin coconut oil-in-water emulsion using polymerized whey protein as emulsifier for Vitamin A delivery

Abstract

Emulsion systems have become an integral part of food manufacturing, mainly as delivery vehicles of sensitive lipophilic nutrients i.e. Vitamin A. Thus, it is crucial to develop emulsions stable enough to protect these nutrients. In this study, virgin coconut oil (VCO)-in-water emulsion was prepared with polymerized whey protein as emulsifier to encapsulate Vitamin A. The VCO droplets were dispersed in water phase, and Vitamin A was dissolved in oil phase. The study aimed at developing VCO-in-water emulsion to encapsulate and protect Vitamin A, in the form of retinyl acetate, and determining physico-chemical characteristics of the emulsion. In vitro analysis was conducted to determine the stability of the emulsion in encapsulating Vitamin A. Three emulsions were prepared at different homogenization speed: 720, 846.7 and 955.8 rpm. The emulsion made with speed setting of 846.7 rpm gave the best visual characteristics, comparable with dairy butter. Thermal analyses using differential scanning calorimeter showed that the emulsion increased the energy requirement to degrade Vitamin A at simulated stomach pH. Also, microscopy results show the emulsion has an average particle diameter of approximately 10 μm, which remained stable at acidic environment of simulated digestion. Therefore, the emulsion is thermodynamically stable and shows minimal coalescence.