Bitter Taste of H-Val-Val-Val-Pro-Pro-Phe-Leu-OH Corresponding to the Partial Sequence (Positions 82 ~ 88) of Bovine ʲ-Casein, and Related Peptides

A heptapeptide, H-Val-Val-Val-Pro-Pro-Phe-Leu-OH, corresponding to the partial sequence of bovine β-casein, positions 82 ~ 88, was synthesized and its bitter taste was measured. Its threshold value of bitterness was 0.14mm. We previously reported that H-Arg-Gly-Pro-Pro-Phe-Ile-OH showed strong bitterness with a threshold value of 0.025 mm. The difference in the characteristic natures of these bitter peptides was found in their N-terminal moiety. We could confirm that, for an increase in the bitterness of peptides, the presence of a basic amino acid in the N-terminal was more effective than an increase in the bulkiness and hydrophobicity with a valine residue.