β-Cryptoxanthin from Citrus juices: Assessment of bioaccessibility using an in vitro digestion/Caco-2 cell culture model

Abstract

β-Cryptoxanthin (β-CX), a provitaminic carotenoid of potential interest for health, is found principally in Citrus fruit in both free and esterified forms. Little is known about the intestinal absorption of β-CX especially with regard to the esterified forms. The aim of this study was to evaluate the absorption of free and esterified β-CX using simulated digestion coupled with the Caco-2 model. Bioaccessibility was investigated by measuring the transfer of carotenoids from different citrus juices into micelles using an in vitro digestion system. Then, carotenoid uptake was evaluated by adding carotenoid-rich micelles (from the in vitro digestion) or synthetic micelles (made from synthetic lipids and carotenoids purified from citrus juice) to human intestinal cells (Caco-2 TC7 clone). Our results showed that β-cryptoxanthin esters (β-CXE) were partially hydrolysed during the in vitro digestion. The bioaccessibility of free β-CX measured was significantly higher (40 (SD 1.05) %) than that of β-carotene (30 (SD 1.9) %) and β-CXE (16 (SD 1.5) %). In the same way, the incorporation of free β-CX (27 (SD 1.01) %) into synthetic micelles exceeded (P<0.05) that of β-carotene (10 (SD 0.7) %) and β-CXE (8.8 (SD 0.4) %). In the case of micelles from in vitro digestion, the uptake of β-carotene, free β-CX and β-CXE forms by Caco-2 cells was 14.3 (SD 1.8), 3.9 (SD 1.3), and 0.7 (SD 0.08) % respectively. These results showed a preferential uptake by Caco-2 cells of β-carotene and free β-CX compared with the two esters of β-CX. © The Authors 2007.