Kokumi γ-glutamyl peptides: Some insight into their evaluation and detection, biosynthetic pathways, contribution and changes in food processing

γ-Glutamyl peptides are small molecular peptides that greatly influence the perception of kokumi taste. Multiple natural peptides, including γ-glutamyl di- and tripeptides and their derivatives, have been isolated and identified from various foodstuffs. Furthermore, some peptides have been effectively synthesized by γ-glutamyl transpeptidase and L-glutaminases. This review summarizes several aspects related to kokumi γ-glutamyl peptides, including their evaluation and quantification methods, biosynthetic pathways, contributions to foodstuffs, and changes during food processing. A better and more accurate understanding of these peptides is essential for further improving food processing and enhancing the desirable characteristics of food.