EFFECT OF ENCAPSULATION CONDITIONS ON CHARACTERISTICS AND ANTIOXIDANT CAPACITY OF NANO EMULSIONS OF LIME ESSENTIAL OIL (Citrus limonia Osbeck) USING THE EMULSION INVERSION POINT METHOD

Abstract

Nano-encapsulation technology was employed to address the challenges of dispersibility and stability associated with lime (Citrus limonia Osbeck) essential oil when used in food applications. The objective of this study was to investigate several technological factors (the ratio of essential oil to coconut oil, the ratio of the oil phase in the total system mass, the ration of emulsifier to oil phase, stirring speed, and emulsifier concentration) to create a nano emulsion system of lime peel essential oil with small particle size and high antioxidant capacity, which can be applied in food processing as a natural additive. The lime peel essential oil used in this study contained 134 volatile compounds, with 25 compounds present at concentrations greater than 0.5%. The results indicate that the optimal conditions for fabricating a high-quality nano emulsion with a particle size of 76.8 ± 1.2 nm, a PDI index of 0.316 ± 0.003, and a zeta potential of -50.8 ± 1.7 mV were as follows: an essential oil-to-coconut oil ratio of 6:4, an oil phase ratio of 10%, an emulsifier-to-oil phase ratio of 1:1, a stirring speed of 1200 rpm, and an emulsifier ratio of Tween 80 and lecithin of 8:2. The lime essential oil nano emulsion exhibited antioxidant capacity comparable to that of pure essential oil. Based on the DPPH method, the IC₅₀ values were 33.51 ± 1.11 mg/mL for the nano-emulsion and 32.63 ± 0.02 mg/mL for pure essential oil. According to the ABTS method, the IC₅₀ values were 29.00 ± 0.36 mg/mL for the nanoemulsion and 45.67 ± 0.58 mg/mL for pure essential oil. The results showed that the lime essential oil nanoemulsion had the potential to be used as a natural additive in food.