NEW MATERIAL:The compound of formula [X and Y are amino acid residue selected from (protected) serine, glutamic acid and γ-glutamic acid; Tau is taurine] and its salt.

EXAMPLE: Glu(glutamic acid)-Ser(serine)-Tau.

USE: A seasoning agent. It has seasoning action free from stimulation and giving refreshing feeling in addition to mild deliciousness and delicate sweetness and is useful as an additive or seasoning for refreshing beverage.

PREPARATION: The objective compound can be produced from each amino acid residue by conventional peptide condensation process such as activated ester process or mixed acid anhydride process. The amino acid for the condensation reaction raw material may be the conventional amino acid having protecting group. The amino group and side-chain functional group which do not take part in the reaction may be protected or the amino group participating in the reaction may be activated. The reaction is carried out under the condition of conventional peptide synthesis.