In vitro digestion and culture in Caco-2 cells to assess the bioavailability of fatty acids: A case study in meat matrix enriched with ω-3 microcapsules.

This work aimed to evaluate the Caco-2 cells as a model to study the epithelial transport of intestinal lipid extracts subjected to in vitro digestion, to establish a standard protocol for the determination of bioaccessibility and bioavailability of fatty acids in meat matrix, especially in those enriched with ω-3 (eicosapentaenoic (EPA) and docosahexaenoic acids (DHA)). Samples were first subjected to in vitro digestion, and then, the intestinal extract was incubated with Caco-2 cells. A first trial was conducted to select the most influencing variables on the fatty acid transport during Caco-2 cell incubation: fat quantity on the intestinal extract, incubation time, and shaking. Then, a second experiment was carried out to determine the influence of these variables, being the fat quantity and the incubation time the most influencing factors on the transport and bioavailability of fatty acids. The effect of shaking was not so marked but seemed to improve the bioavailability of saturated fatty acids. This study also allows establishing the most suitable conditions: intestinal extracts with 30 mg of fat, longer incubation times (8 h), and shaking, achieving active and passive fatty acid transport without compromising the integrity of the Caco-2 cell monolayer. The accurate results obtained for major and minor fatty acids, especially EPA and DHA are remarkable, due to the interest in these bioactive compounds. Thus, this study provides a combined protocol based on static in vitro digestion followed by Caco-2 cell incubation to assess the bioaccessibility and bioavailability of fatty acids in meat samples.