Identification of extraction pH and cultivar associated aromatic compound changes in spray dried pea protein isolate using untargeted and targeted metabolomic approaches

Pea proteins are promising plant proteins in the food industry but their flavor limits consumer acceptance. In this study, the impacts of extraction pH (8.5, 9.5 and 10) and cultivars (Agassiz and Trapeze) on the aromatic flavor profile of spray-dried pea proteins at each one of the three alkaline extraction-isoelectric precipitation steps were investigated by a headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GCMS) metabolomic approach. In total, 53, 54, and 48 representative compounds were obtained for each extraction step, respectively, and were used by Venn diagram, principal component analysis, hierarchical cluster analysis, and heatmap analysis to demonstrate the flavor variations among pea proteins with different extraction pH and cultivars. In addition, the changes of 7 beany-flavor markers during the extraction process were tracked and results showed that, in general, their content peaked in the second extraction step while 28% of the comparisons between the initial and final step showed a significant difference. The results of this study could provide a better understanding of flavor development of pea proteins during their production.