Quantitative analysis of cyclic prolyl-hydroxyproline in human plasma after ingestion of gelatin and gelatin hydrolysates

Abstract

This study examined the changes in concentration of cyclic prolyl-hydroxyproline (cyclo(Pro-Hyp)) in human plasma after ingestion of gelatin, gelatin hydrolysate (collagen peptide; CP) and low-molecular weight CP. This human study showed that gelatin ingestion significantly increased cyclo (Pro-Hyp) levels in plasma from 1 hour after ingestion as well as CP and low-molecular weight CP. Furthermore, the ratio of cyclic Pro-Hyp to the total content of cyclic and liner Pro-Hyp in plasma after gelatin ingestion was highest among other CP ingestions. These results suggested that gelatin can be candidate for active components of the health benefits by gelatin and CP ingestion. In addition, in case of gelatin, large individual differences in cyclo (Pro-Hyp) concentration was observed in plasma at each time point after ingestion. It might indicates that cyclo (Pro-Hyp) concentration into plasma is affected not only molecular size of gelatin products, but also cyclization ability in each subjects. A further study for elucidating the mechanism of peptide cyclization in gastrointestinal tract is now in progress.