Vitamin E Encapsulation in Plant-Based Nanoemulsions Fabricated Using Dual-Channel Microfluidization: Formation, Stability, and Bioaccessibility

In this study, vitamin E was encapsulated in oil-in-water nanoemulsions fabricated using a dual-channel microfluidizer. A long chain triacylglycerol (corn oil) was used as a carrier oil and a biosurfactant (quillaja saponin) was used as a natural emulsifier. The impact of vitamin-to-carrier oil ratio on the formation, storage stability, and bioaccessibility of the nanoemulsions was determined. The lipid droplet size formed during homogenization increased with increasing vitamin content, which was attributed to a large increase in lipid phase viscosity. The storage stability of the nanoemulsions decreased as the vitamin content increased because the larger lipid droplets creamed faster. The rate and extent of lipid hydrolysis in the small intestine decreased as the vitamin content increased, probably because the vitamin molecules inhibited the ability of lipase to reach the triacylglycerols inside the lipid droplets. Vitamin bioaccessibility decreased as the vitamin level in the lipid phase increased, which was attributed to the reduced level of mixed micelles available to solubilize the tocopherols. The optimized nanoemulsion-based delivery system led to a relatively high vitamin bioaccessibility (53.9%). This research provides valuable information for optimizing delivery systems to increase the bioaccessibility of oil-soluble vitamins.