A method of preparing a synthetic butter flavor having enriched milk flavor and butter flavor, comprising the steps of hydrolysing a milk fat with a lipolytic enzyme and then oxidizing the hydrolysate of the milk fat by ultraviolet irradiation is disclosed. The hydrolysate of the milk fat is preferably oxidized by ultraviolet irradiation to have a POV of 1.5 to 9.0, in particular 4.0 to 7.5.
