Kruger, JohanitaStuetz, WolfgangFrank, Jan2019-06-192019-05Kruger, J., Stuetz, W. & Frank, J. 2019, 'Iron, catechin, and ferulic acid inhibit cellular uptake of β-carotene by reducing micellization', Journal of Agricultural and Food Chemistry, vol. 67, no. 20, pp. 5792-5800.0021-8561 (print)1520-5118 (online)10.1021/acs.jafc.9b01417http://hdl.handle.net/2263/70253Green leafy vegetables have low β-carotene bioavailability, which we hypothesized to be, at least in part, due to high contents of fiber, minerals, and phenolics. We investigated the effects of pectin (40–120 μg/mL), iron (50–150 μg/mL), ferulic acid (30–90 μg/mL), and catechin (50–150 μg/mL), in a model system, on β-carotene micellization (in vitro digestion) and intestinal absorption (Caco-2 cell model). Iron, pectin, ferulic acid, and catechin on average reduced (p < 0.05) β-carotene micellization (1.49 ± 0.05 μmol/L) by 66.9, 59.3, 43.2, and 51.7%, respectively. Iron reduced micellization by precipitating bile salts from solution and ferulic acid and catechin by inhibition of pancreatic lipase. β-Carotene uptake by Caco-2 cells (2.63 ± 0.22%) was reduced (p < 0.05) by 37.4, 70.1, 77.0, and 75.1%, respectively, when it was digested with pectin, iron, ferulic acid, or catechin. However, when individual test compounds were added to already micellized β-carotene, they did not inhibit β-carotene uptake. The large reductions in β-carotene micellization observed in vitro warrant further investigation in humans using model green leafy vegetable systems to elucidate their relevance under real-life conditions.enThis document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Agricultural and Food Chemistry, © 2019 American Chemical Society after peer review and technical editing by the publisher.BioavailabilityDietary inhibitorsGreen leafy vegetablesPectinIronPancreatic lipaseIntestinal absorptionIn-vitro digestionsCellular uptakeBeta caroteneSaltsPhenolsMicellizationFlavonoidsBiochemistryCellsPostprint Article