Optimizing Fucoidan Encapsulation in a W1/O/W2 Double Emulsion through an Ultrasound-Assisted Process and Response Surface Methodology

Fucoidan from marine brown algae has been known to exert several health benefits, primarily antioxidant and anticancer properties. The primary goal of this research was to encapsulate fucoidan in stable water-in-oil-in-water (W1/O/W2) emulsions using an ultrasound technique. We optimized primary emulsion and double emulsion formulations using the response surface methodology (RSM). The formulation for primary emulsion and double emulsion is based on lecithin as the lipophilic surfactant concentration (0–5%), sonication time (20, 25, and 30 min), and hydrophilic surfactant Tween 80 (0–2.5%), respectively. Both emulsions are further characterized based on variables such as drop size, antioxidant activity, gravitational stability, peroxide value, and encapsulation efficiency. Based on RSM, the double emulsion with optimum conditions (sonication time, 25 min; internal emulsifier lecithin, 2.6%, sonication amplitude, 71%; and external emulsifier Tween 80, 1.2%) showed a small drop size (726 nm), antioxidant activity (91.33%), a stability of 85.33%, and an encapsulation efficiency of 90.36. Further optimized and stable double emulsions were assayed during 45 days of storage at a temperature of 37 °C. The results showed a slight change with minimal percentage loss of encapsulation efficiency from 90.36 to 86.78%.