ROLE OF BASIC AND ACIDIC FRAGMENTS IN DELICIOUS PEPTIDES (LYS-GLY-ASP-GLU-GLU-SER-LEU-ALA) AND THE TASTE BEHAVIOR OF SODIUM AND POTASSIUM-SALTS IN ACIDIC OLIGOPEPTIDES

The role of the acidic fragment (Asp-Glu-Glu) in delicious peptides wa s investigated in detail by using the Na+ or K+ salts of acidic oligop eptides so that amount of Na+ or K+ intake of peptides composed of aci dic amino acids could be varied by changing their sequences, The taste of these peptides was confirmed to vary with Na+ or K+ intake, Additi onally, in order to study the role of basic (Lys-Gly) and acidic (Asp- Glu-Glu) fragments in delicious peptides for producing the taste, five delicious peptide analogs, Ser-Leu-Ala-Lys-Gly-Asp-Glu-Glu, Ser-Leu-A la-Asp-Glu-Glu-Lys-Gly, Lys-Gly-Ser-Leu-Ala-Asp-Glu-Glu, Lys-Gly-Asp-G lu-Glu, and Glu-Glu-Asp-Gly-Lys, were synthesized, The intensity of th e umami and/or salty taste of these peptides and their Na salts was al most the same, despite their chemical structures being different, Thes e results indicate that the acidic fragment as well as the basic fragm ent plays an important role in the taste production and intensity of d elicious peptides, and that an umami or salty taste can be produced by the localization of the cation of the basic fragment and the anion of the acidic fragment.