Stability and Kinetic Study of Vitamin C containing Hydrogenated and Middle-Chain Triglyceride Coconut Oil-Based Double Emulsion

Vitamin C or ascorbic acid, is an organic compound that is highly required by human since it acts as antioxidant, help increase metabolism, and improves the immune system. Vitamin C is easily oxidized and damaged during storage due to several external factors such as light, metal, shear, etc. The encapsulation technique is able to improve the stability as well as the activity of Vitamin C in order to protect the bioactive compound from deleterious external factors. Coconut oil which is composed of about 50% lauric acid, has an antiviral property. This research aimed to obtain the stable water-in-oil-in-water (W1/O/W2) double emulsion using coconut oil upon the incorporation of Vitamin C. Hydrogenated (HCNO) and Medium-Chain Triglycerides (MCT) coconut oil was used as the oil phase, and various emulsifiers such as Tween-20 0.5%, Tween-20 1%, and Tween-20 0.5%/ PgPr 0.5% were applied to strengthen the outer interfacial layer. The double emulsion stability was monitored macroscopically, and the destabilization kinetics was studied using the zero and first-order kinetic models. It turned out that the HCNO-based double emulsion demonstrated higher stability compared to the MCT-based double emulsion. The lowest destabilization rate constants of 4.5 x 10-3 h-1 and 6.8 x 10-3 h-1 were obtained for HCNO and MCT-based double emulsions both stabilized with Tween-20 0.5%, respectively. The coconut oil-based double emulsion enriched with Vitamin C would be potentially developed for various functional food applications.