The influence of excipient nanoemulsions on β-carotene bioaccessibility from commercial dietary supplements (tablets or soft gels) was studied employing an in vitro gastrointestinal tract (GIT) model. Excipient nanoemulsions were formulated from long or medium chain triglycerides (LCT or MCT) to determine the impact of lipid type on carotenoid bioaccessibility. Dietary supplements were tested using the GIT model in the absence or presence of excipient nanoemulsions. β-carotene bioaccessibility from tablets (0.3%) or soft gels (2.4%) was low when tested in isolation. LCT nanoemulsions greatly improved β-carotene bioaccessibility from tablets (20%) and slightly improved it from soft gels (5%), whereas MCT nanoemulsions only slightly improved bioaccessibility. These results were attributed to the ability of large carotenoid molecules to be incorporated into large mixed micelles formed by LCT digestion but not by small ones formed by MCT digestion. Our results indicate that excipient nanoemulsions have considerable potential for improving nutraceutical bioavailability from dietary supplements.
Keywords: bioaccessibility; excipient foods; lipid digestion; nanoemulsions; nutraceuticals; β-carotene.