Analytical evaluation of bioactive small peptides on their intestinal absorption and bioavailability

Small peptides with di- or tripeptide length have been known as bioactive food components to prevent lifestyle-related diseases (e.g. hypertenstion). Although they must be absorbed into the blood circulation or accumulated in targeted tissues after their intake, the bioavailability was still uncertain due to limitations of analytical methods. Thus, the aim of this study was to develop analytical methods to measure these small peptides based on mass spectrometry (MS) techniques. In this study, a 2,4,6-trinitrobenzenesulfonate-derivatized liquid chromatography- multiple reaction monitoring-tandem mass spectrometry (LC-MRM-MS/MS) technique was developed to significantly enhance the sensitivity of small amines including peptides. The evidence of phytic acid to improve poor detection of small peptides (< 500 Da) by matrixassisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS) was also demonstrated. Here, this review article summarizes these developed MS techniques as well as the resulting bioabailability and intestinal absorption behavior of these bioactive small peptides based on the established analytical methods.