Studies of Bitter Peptides from Casein Hydrolyzate. IV. Relationship between Bitterness and Hydrophobic Amino Acids Moiety in the C-Terminal of BPIa (Arg–Gly–Pro–Pro–Phe–Ile–Val)

Abstract

Abstract In the synthetic studies of bitter peptide BPIa (Arg–Gly–Pro–Pro–Phe–Ile–Val), we synthesized several BPIa analogs to elucidate the participation of the hydrophobic amino acids moiety in the C-terminal in the bitter taste exhibited by BPIa. The syntheses of the peptides were performed by the usual MA (mixed anhydride) and DCC (dicyclohexylcarbodiimide)–HOBt (1-hydroxybenzotriazole) method, and the bitterness of the peptides was organoleptically determined. The BPIa analogs in which more than two hydrophobic amino acids were located in the C-terminal exhibited a bitter taste as strong as that of BPIa.