Peptide Profiling of Food Protein Hydrolysates via Ultra-Performance Liquid Chromatography Electrospray Ionisation-Tandem Mass Spectrometry (UPLCESI-MS/MS) Coupled to a Quadruple Time-of-Flight (qTOF) Analyser

The profiling of peptides in food protein hydrolysates or digests is of vital importance in order to understand the pattern of hydrolysis/digestion of proteins, their technofunctional properties or the release of bioactive peptides (BAPs). The identification of peptides allows the performance of detailed studies to establish their techno- and biofunctional properties and can assist researchers, food and pharmaceutical companies in the targeted production of specific peptide containing protein hydrolysates. Furthermore, the identification of peptides from food protein hydrolysates can help in the understanding of the biological function of BAPs and support documentation for the approval of health/nutritional claims. This chapter describes how to perform peptide profiling of food protein hydrolysates/digests using a proteomic platform consisting of an ultra-performance liquid chromatography electrospray ionisation-tandem mass spectrometry (UPLCESI-MS/MS) coupled to a quadruple time-of-flight (qTOF) analyser. Moreover, details in relation to sample preparation, MS data acquisition, data processing for peptide identification (including de novo sequencing) and peptide sequence validation approaches particularly using PEAKs® software are provided herein. The information provided may be of relevance to those studying food proteins and peptides, protein hydrolysates, protein digestion, protein and hydrolysate technofunctional properties and the identification of peptides in order to determine their mechanism of action/biological activity or their interaction with other food components.