FOOD SCIENCE

    Next Articles

Influence of Delivery Systems on the Absorption and Transport of Theaflavins in Caco-2 Cell Model

Yu-Ting LU 2, 2, larkin liu 2   

  • Received:2025-06-16 Revised:2025-09-09 Online:2025-09-23 Published:2025-09-23

Abstract: Theaflavins (TFs), as functional polyphenols in black tea, exhibit extremely low bioavailability, which severely limits their application in functional foods. Previous studies have shown that water-in-oil (W/O) emulsions can significantly improve the bioaccessibility of TFs. Building on this, the present study investigated the effects of digested aqueous solutions, oil-water mixtures and water-in-oil emulsions on the cellular uptake and cellular transport of TFs based on the Caco-2 cell model. The results demonstrated that the cellular uptake rate of TFs in the W/O emulsion reached 11.02%, which was 3.13 times and 2.50 times higher than that of the aqueous solution (3.52%) and the oil-water mixture (4.41%), respectively. After 4 h of incubation, TF, TF3G, TF3'G, and TFDG from the emulsion were all taken up by the cells, with uptake rates of 5.83%, 1.36%, 2.63%, and 1.21%, respectively. In contrast, only TF was detected in the oil-water mixture and aqueous solution groups. The cellular secretion rate assay revealed that, the secretion rates of TFs in the oil-water mixture and aqueous solution increased gradually within the 1 to 4 h,whereas the W/O emulsion exhibited a linear increase. After 4 h of incubation, the cellular secretion rate of TFs in the W/O emulsion reached 28.72%, which was 3.6 times and 2.5 times higher than that of the aqueous solution and the oil-water mixture, respectively. Only two monomers, TF and TF3G, were detected in the secretion from the aqueous solution group, whereas all four TFs monomers were identified in both the emulsion and oil-water mixture groups. The secretion rates of TF, TF3G, TF3'G, and TFDG from the emulsion were 16.32%, 2.15%, 3.97%, and 6.28%, respectively, corresponding to 2.39-fold, 1.90-fold, 1.78-fold, and 4.49-fold increases compared to the oil-water mixture. The bioavailability of TFs in the W/O emulsion was 22.95%, representing an 11.3-fold and 4.4-fold enhancement compared to the aqueous solution and oil-water mixture, respectively. This study demonstrates that W/O emulsion significantly improves both the cellular absorption and bioavailability of TFs, providing an important theoretical foundation for their application in the functional food industry.

Key words: Water-in-oil emulsion, Theaflavins, Caco-2 cell model, Bioavailability

CLC Number: