The stabilization of kenaf leaves extract co-loaded W 1 /O/W 2 double emulsion by emulsifier mixtures of sodium caseinate-Tween20-β-cyclodextrin

Abstract

Water-in-oil-in-water (W1/O/W2) double emulsion (DE) is often used for hydrophilic bioactives encapsulation. However, the stabilization of food-grade DE is difficult due to its complex structure and limited emulsifier choices. Thus, this paper studies the stabilization of DE containing ethanolic kenaf leaves extract by emulsifier mixture (EM) containing sodium caseinate, Tween-20, and β-cyclodextrin. The particle size, polydispersity index, creaming index, encapsulation efficiency, and droplet morphology were observed for 5 weeks storage. Overall, all DE samples did not undergo phase separation, with a noticeable increase in viscosity throughout storage. The morphology and functional groups also showed spherical droplet shape and interaction changes after emulsification. DE stabilized by 2.5% and 4.0% (w/w) EM had consistent droplet size and distribution, encapsulation efficiency > 98%, and highest viscosity value up to 35-day storage at 25℃. Specifically, DE with 4.0% (w/w) EM showed good resistance under pH changes. In conclusion, double emulsion stabilized by sodium caseinate, T20, and β-cyclodextrin are stable up to 5 weeks at 25°C, potentially to be applied in food and beverage applications.