PURPOSE: To prevent the deterioration of a coffee flavor to stably retain the excellent coffee flavor for a long period by utilizing a specific fraction obtained by treating an aqueous solvent extract of a roasted coffee with an ultrafiltration membrane.

CONSTITUTION: Coffee beans are roasted, ground and subsequently extracted with hot water or a water-containing water-miscible organic solvent (e.g., water- containing methanol). The obtained aqueous solvent extract of the roasted coffee is treated with an ultrafiltration membrane having a fractionation mol.wt. of approximately 6000 and a non-passed fraction having fractionation mol.wts. of ≥6000 is collected. The obtained fraction having a flavor deterioration- preventing effect is added to a coffee extract prepared from a roasted coffee, mixed coffee flavors, coffee-flavored beverages compounded with the flavors, etc., to prevent the deterioration of the coffee flavors.