Current understanding of transport and bioavailability of bioactive peptides derived from dairy proteins: a review

Dairy protein-derived bioactive peptides (DBPs) have potential benefits for human health. However, their transport mechanisms and bioavailability from intestinal lumen to bloodstream are not well understood. This review summarises current understanding of their transport mechanisms across the intestinal membrane (peptide transport 1, paracellular route, transcytosis and passive transcellular diffusion) and the bioavailability of DBPs in animal and human studies. Some DBPs can escape the degradation of peptidase and reach the bloodstream at concentrations of micromolar range, and keep intact for several minutes to hours. The presences of brush-border peptidases at the site of absorption and other peptidases in the blood, along with the peptide properties, such as molecular size and weight, stability to proteases, hydrophobicity and charge, determine their bioavailability. Developing novel analytical tools for accurate measurement and study of the transport, metabolism, and bioavailability of DBPs in vivo are expected.