PROBLEM TO BE SOLVED: To provide a mustard paste stably keeping the flavor component of mustard. SOLUTION: The objective mustard paste keeping the flavor component is produced by adding a catechin such as epigallocatechin to pasty mustard or Japanese horseradish. Catechin is a water-soluble component extracted from tea leaf and the material commercially available generally in the name of 'Tea Extract' can be used for the purpose. Epigallocatechin is an isomer of catechin gallate fractionated from catechin and is a catechin component existing in tea leaf tannin in largest amount.
