Tripeptides bitter

Otagiri et al. (22) used model peptides composed of arginine, proline, and phenylalanine to ascertain the relationship between bitter flavor and chemical structure. They reported that the presence of the hydrophobic amino acid at the C terminus and the basic amino acid at the N terminus brought about an increase in the bitterness of di- and tripeptides. They further noted a strong bitter taste when arginine was located next to proline and a synergistic effect in the peptides (Arg)r(Pro) ,-(Phe) (/ = 1,2 m, n = 1, 3) as the number of amino acids increased. Birch and Kemp (23) related the apparent specific volume of amino acids to taste. 

On Table V a series of bitter di- and tripeptides synthesized by Shiraishi (68) is given. 

The contribution of the d enantiomers to the characteristic taste of foods is currently being evaluated, but it is clear that the d enantiomers generally taste sweeter , or at least less bitter , than do their l isomers. Of course, kitchen preparation can involve many subtle chemical changes that enhance the attractiveness of natural foodstuffs, including racemisation (Man and Bada, 1987) therefore d enantiomers may be introduced in this way. Peptides are taste contributors, for example the bitter-tasting dipeptides Trp—Phe and Trp—Pro and the tripeptide Leu—Pro—Trp that are formed in beer yeast residues (Matsusita and Ozaki, 1993). 

Wu, J. and Aluko, R.E. (2007) Quantitative structure-activity relationship study of bitter di- and tripeptides including relationship with angiotensin I-converting enzyme inhibitory activity./. Pestic. Sci., 13, 63-69. 

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