Amino Acids, α-Peptides, and Their Related Kokumi Substances

In the last decade, the number of studies published on kokumi peptides has increased and many novel kokumi peptides have been introduced. Kokumi substances are defined as taste-related substances that modify flavor characteristics, such as complexity (thickness of taste), mouthfulness, and lastingness (continuity), when added to basic taste solutions or food, but are themselves tasteless at the added doses. Among the kokumi peptides and related compounds reported to date, compounds that match the definition of a kokumi substance are discussed in this chapter. Several α-peptides and N-acyl-amino acids have been reported to have lower threshold values in food than in water in sensory evaluations with nose-clips. Therefore, these α-peptides and N-acyl-amino acids may be regarded as kokumi substances.