STUDIES ON BITTER PEPTIDES FROM CASEIN HYDROLYZATE .14. BITTER TASTE OF SYNTHETIC ANALOGS OF OCTAPEPTIDE, ARG-GLY-PRO-PHE-PRO-ILE-ILE-VAL, CORRESPONDING TO THE C-TERMINAL PORTION OF BETA-CASEIN

In order to elucidate the relationship between the chemical structure and bitter taste of the C-terminal portion of beta-casein, some analog ues, in which the phenylalanine residue was substituted by D-phenylala nine, lysine, glycine, glutamic acid or L-pyrenylalanine, were synthes ized. Sensory analyses and CD spectra showed that the location of a hy drophobic amino acid with the L-configuration between the two proline residues should be important for this series of peptides to produce a strong bitterness.