The dose-response effect of lecithin on carotenoid bioaccessibility and Caco-2 cell uptake.

Previous results have been mixed as to whether the emulsifying agent lecithin increases carotenoid bioaccessibility and Caco-2 cellular uptake. The dose-response effect of lecithin (0-5 mg) on carotenoid bioaccessibility and Caco-2 cellular uptake was investigated in vitro using a mixture of β-carotene, lycopene, lutein, zeaxanthin and astaxanthin. Resulting micelles were incubated with Caco-2 cells for 4 h. Carotenoids in chyme, micelle, and cellular fractions were quantitated using HPLC-DAD and HPLC-MS/MS. Lecithin-micelle interactions were visualized using confocal microscopy. A lecithin dose of 1 mg improved carotenoid bioaccessibility ∼2× and led to increased Caco-2 cell uptake of the carotenes tested, but no change in xanthophylls tested, as compared to the control group (P < 0.05). Doses of lecithin ≥3 mg did not improve carotenoid bioaccessibility or Caco-2 cell uptake and produced oil droplet aggregation. These results suggest that limited doses of lecithin should be investigated in relation to maximizing carotenoid bioavailability in humans.