Comparative Evaluation of Micellization and Cellular Uptake of <i>β</i>‑Carotene Affected by Flavonoids

Based on <i>in vitro</i> digestion, micellar synthesis, and Caco-2 cell model, this study investigated the effects of typical flavonoids in citrus (naringenin, naringin, hesperetin, hesperidin, quercetin, and rutin) at different doses on the micellization and cellular uptake of <i>β</i>-carotene. In <i>in vitro</i> digestion, low-dose flavonoids enhanced <i>β</i>-carotene bioaccesssibility by regulating the stability and dispersibility of the intestinal medium, particularly quercetin, which significantly increased the bioaccessibility by 44.6% (<i>p</i> < 0.05). Furthermore, naringenin, hesperetin, hesperidin, and quercetin enhanced the micellar incorporation rate of <i>β</i>-carotene; however, naringin and rutin exhibited an opposite effect, particularly naringin, which significantly reduced it by 71.3% (<i>p</i> < 0.05). This phenomenon could be attributed to the high solubility of naringin and rutin in micelles, resulting in a competitive inhibitory effect on <i>β</i>-carotene. Besides, all treatments significantly enhanced <i>β</i>-carotene cellular uptake (<i>p</i> < 0.05) by promoting the expression of scavenger receptor class B type I and Niemann-Pick C1-Like 1.