Institute of Nutritional Sciences , University of Hohenheim , Garbenstraße 28 , 70599 Stuttgart , Germany.
Department of Food Science and Institute for Food, Nutrition and Well-being , University of Pretoria , Private Bag X20 , Hatfield 0028 , South Africa.
J Agric Food Chem. 2019 May 22;67(20):5792-5800. doi: 10.1021/acs.jafc.9b01417. Epub 2019 May 14.
Green 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.
绿叶蔬菜的 β-胡萝卜素生物利用率较低，我们推测这至少部分归因于其高纤维、矿物质和酚类含量。我们在模型系统中研究了果胶（40-120μg/mL）、铁（50-150μg/mL）、阿魏酸（30-90μg/mL）和儿茶素（50-150μg/mL）对β-胡萝卜素胶束化（体外消化）和肠道吸收（Caco-2 细胞模型）的影响。铁、果胶、阿魏酸和儿茶素平均分别降低（p<0.05）β-胡萝卜素胶束化（1.49±0.05μmol/L）66.9%、59.3%、43.2%和 51.7%。铁通过沉淀胆汁盐从溶液中沉淀，阿魏酸和儿茶素通过抑制胰脂肪酶来降低胶束化。Caco-2 细胞对β-胡萝卜素的摄取（2.63±0.22%）分别降低（p<0.05）37.4%、70.1%、77.0%和 75.1%，当与果胶、铁、阿魏酸或儿茶素消化时。然而，当将单独的测试化合物添加到已胶束化的β-胡萝卜素中时，它们并没有抑制β-胡萝卜素的摄取。体外观察到的β-胡萝卜素胶束化的大量减少值得在使用模型绿叶蔬菜系统的人体中进一步研究，以阐明它们在现实条件下的相关性。
