PURPOSE: To prevent the color change of a food made from wheat flour and colored with the pigment of gardenia, by using the gardenia pigment fractionated and purified with a porous adsorbent resin.

CONSTITUTION: The fruit of gardenia is extracted with water or an about 20% alcohol solution to separate the gardenia pigment from the fruit. The extract liquid is made to contact with a porous adsorbent resin to effect the adsorption of the yellow pigment and green-colored substance from the gardenia pigment to the resin. The resin is treated with a 25% alcohol solution to elute the green- colored substance, and then with 50% alcohol solution to separate the yellow pigment. The eluate is filtered and concentrated to obtain a concentrated liquid or pulverized to obtain purified gardenia pigment. When a food made from wheat flour such as vermicelli is colored with the pigment, the obtained yellow color lasts for a long period.