In order to investigate the relationship between chemical structure and bitter taste, the bitter peptide BPIc (Val–Tyr–Pro–Phe–Pro–Pro–Gly–Ile–Asn–His) isolated from casein hydrolyzate by Minamiura et al. and its analogs and fragments were synthesized. BPIc, whose threshold value of bitter taste was 0.05 mM, was found to be one of the most bitter compounds, like quinine and phenylthiourea. However, [Gly5,6]- and [Gly9,10]-BPIc, and N-terminal octa- and heptapeptide fragments of BPIc possessed much weaker bitterness than BPIc. The results suggested that 5,6-proline and the basic nature of C-terminal are necessary for the strong bitterness exhibited by BPIc.
为了研究
化学结构与苦味之间的关系,研究人员合成了 Minamiura 等人从
酪蛋白水解物中分离出的苦味肽 B
PIc(Val-Tyr-Pro-Phe-Pro-Gly-Ile-Asn-His)及其类似物和片段。研究发现,B
PIc 的苦味阈值为 0.05 mM,与
奎宁和苯
硫脲一样是最苦的化合物之一。然而,[Gly5,6]- 和 [Gly9,10]-B
PIc 以及 B
PIc 的 N 端八肽和七肽片段的苦味比 B
PIc 弱得多。结果表明,5,6-脯
氨酸和 C 端的碱性是 B
PIc 表现出强烈苦味的必要条件。