Enhancing physical and chemical stability of a water-in-oil gelled-in-water multiple emulsion containing omega-3 polyunsaturated fatty acids and curcumin by Draper-Lin Composite Design

Omega-3 polyunsaturated fatty acids and curcumin have exhibited therapeutic benefits and positive health impacts. However, their limited solubility in aqueous systems, coupled with low bioaccessibility and bioavailability, high chemical reactivity, and instability under ambient conditions, contribute to their degradation, resulting in the deterioration and loss of food quality. This study aims to design, develop, and optimize a water-in-oil gelled-in-water (W 1 /Og/W 2 ) emulsion against physical and chemical destabilization mechanisms. This emulsion serves the dual purpose of encapsulating and safeguarding the lipid phase –comprising a previously optimized oleogelified fish oil concentrate– against oxidation processes, and simultaneously facilitate the transport and controlled release of curcumin. For that, a Draper-Lin Composite Design was implemented to assess the impact of the relevant factors on the physicochemical stability and curcumin retention capacity of the W 1 /Og/W 2 emulsion. Physically stable multiple emulsions have been achieved for 30 days post-production, exhibiting mean droplet sizes smaller than 23.114 μm. The findings underscore the importance of optimizing emulsifier concentrations to mitigate lipid oxidation and emphasize the crucial role of hydrophilic emulsifiers in simultaneously controlling droplet size and enhancing curcumin retention capacity of the W 1 /Og/W 2 emulsion. Subsequent application of mathematical models and multi-response surface methodology led to the identification of an optimal formulation: Cet = 8.1 wt%, φ OE/WE = 89.8 wt%, HSs = 19,600 rpm, φ (W1/O)/W2 = 5.1 wt%, Ce2 = 9.6 wt% and HSm = 6400 rpm. These results provide a valuable foundation for the design of multiple emulsions, to stabilize and efficiently transport bioactive compounds for health benefits. • A stable water-in-oil gelled-in-water emulsified delivery system for 30 days has been developed. • The multiple emulsions obtained showed d [4,3] less than 23.114 μm 30 days post-production. • To reduce the total emulsifier concentration in W 1 /Og (range from 6 to 14 wt%) is crucial to decrease lipid oxidation. • The emulsifier concentration in the multiple emulsion (range from 5 to 13 wt%) is key variable. • The optimal formulation achieved was: Cet = 8.1 wt%, φ OE/WE = 89.8 wt%, HSs = 19,600 rpm, φ (W1/O)/W2 = 5.1 wt%, Ce2 = 9.6 wt% and HSm = 6400 rpm.