In vitro bioaccessibility and monolayer uptake of lutein from wholegrain baked foods

Lutein-enriched foods would contribute towards promoting the consumption of this important carotenoid. In the current study cookies, muffins, and flatbreads were produced at three enrichment levels (0.5, 1.0 and 2.0 mg lutein per serving) to investigate lutein bioavailability in vitro. Foods were subjected to in vitro simulation of human upper gastrointestinal digestion coupled with a Caco-2 monolayer absorption assay. Digestive conditions representative of the fed state conditions associated with significantly higher lutein bioaccessibility compared with the fasted state (p < 0.001). Lutein bioaccessibility of cookies and muffins was higher than flatbreads due to their elevated fat content, measured under either fed or fasted conditions. Lutein concentration in the aqueous phase was the most important factor in determining apical cell uptake of lutein, with cookies and muffins exhibiting a higher lutein uptake than flatbreads (p < 0.05). As commonly consumed foods, lutein-enriched cookies, muffins, and flatbreads have the potential to improve lutein intake.