Bioavailability of whey proteins using a CaCo2/HT29 co-culture model

Whey proteins are prized for their nourishment and their bioactive components. The aim of this study was to identify whey peptides that are transported across the intestinal barrier and are therefore available to provide a health benefit to downstream cells. Commercially available whey proteins (whey protein isolate, β-lactoglobulin and bovine serum albumin) and a whey-based sports product were subjected to a static in vitro gastrointestinal digestion using COST INFOGEST method. The intestinal barrier co culture model, CaCo2-HT-29, was exposed to these digesta samples, at physiologically relevant concentrations. After a two hour incubation, apical and basolateral solutions were analysed for peptide content by Ultra-Performance Liquid Chromatography/Electrospray Ionisation-High Resolution Tandem Mass Spectrometry (UPLC/ESI-HR-MS/MS). The peptides were identified using the Proteome Discoverer 1.4 software against the Bos taurus database (UniProt taxon ID 9913). The false discovery rate of peptide identification was set to FDR = 0.01. Novel peptides were identified in the basolateral solutions of cells exposed to different whey sample. In addition, several known bioactive peptides were found to cross the intestinal barrier. In conclusion, gut transit generates bioactive peptides from whey that are bioavailable across the intestinal barrier. Our work provides a proof of concept for combining in vivo and in silico digestion approach for better understanding the activity of digestive enzymes and potential release of bioactive sequence through the digestive tract.