Applicability of an in vitro model to assess the bioaccessibility of vitamins A and E from fortified commercial milk

In vitro models based on human physiology have been developed as simple, inexpensive and reproducible tools to predict the bioavailability of different food components. Our aim was to assess the applicability of an in vitro digestion model to estimate the bioaccessibility of fat-soluble vitamins contained in commercially available liquid milk. For vitamin A, the rate and degree of hydrolysis of both endogenous and synthetic ester forms varied according to the type of milk (skimmed versus whole), although the amount of free retinol transferred into micelles was equivalent. For vitamin E, there was apparently no hydrolysis of tocopheryl acetate contained in fortified whole milk, while it was incomplete in the skimmed milk. Overall, in vitro results appear consistent with in vivo observations supporting the potential applicability and predictive value of the in vitro approach to assess the bioavailability of fat-soluble vitamins from dairy matrices.