Evaluation of antioxidant efficacy of quercetin encapsulated in micelles, mixed micelles, or liposomes in oil-in-water emulsions

Quercetin was encapsulated in polyoxyethylene laurylether (Brij 35®) micelles, 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) liposomes and Brij 35®/DMPC mixed micelles. These obtained formulations were then physically characterized for their particle size, morphology, physical stability and polydispersity index. All quercetin formulations were evaluated for their antioxidant efficiency in two oil-in-water emulsion systems and compared to the one of free quercetin. In short-term assays, results showed that among the tested formulations, quercetin liposomal form offered superior antioxidant protection, in comparison with polymer micelles or mixed micelles form or free quercetin. These results were attributed to a better synergistic effect of liposomal quercetin formulation with tocopherols present in the oil phase of the emulsion. However, in long-term assay, the loaded quercetin showed chemical degradation over the long term in the liposomal form, thus limiting its long-term antioxidant effectiveness in food emulsions.