Effect of molecular weight on the transepithelial transport and peptidase degradation of casein-derived peptides by using Caco-2 cell model

The transepithelial transport routes of casein-derived peptides with different molecular weights (MWs) were investigated using a Caco-2 cell monolayer. The peptidase hydrolysis during transport was also studied. The results indicate that the paracellular route was the main pathway for F1 (1600-1300 Da) and F2 (1000-500 Da), and the bioavailabilities were 10.66% and 9.54%, respectively. Peptidase hydrolysis results reveal that brush-border peptidases (BBPs) as well as some other peptidases were responsible for peptide degradation in the paracellular route. The maximum hydrolysis rate of the former was 6.91 and 5.59 mu M Gly/min for the latter. However, PepT1 was involved in the transport of F3 (<500 Da) and its bioavailability was 16.23%. BBPs were the main peptidases involved in the PepT1 transport and the maximum hydrolysis rate was 11.4 mu M Gly/min. Furthermore, we found that the amino acid sequence of di- and tripeptides might affect their bioavailabilities significantly. (C) 2016 Published by Elsevier Ltd.