PURPOSE: To obtain the food such as a cut leaf-containing sushi or a sour agent or megrim medicine containing tartaric acid by using grape leaves or young bunches pinched on a top-pinching work as raw materials.

CONSTITUTION: Grape leaves or young bunches pinched on a top-pinching work are used as food materials to prepare foods such as INARIZUSHI (flavored boiled rice wrapped up with fried bean curd) containing the cut leaves or rice balls containing the cut leaves. These foods can be wrapped with the grape leaves or dished on the grape leaves. Young sprouts or young leaves until the middle of May are suitable for the foods, and the young bunches pinched on the top pinching work can also be used for the foods. Grape leaves, etc. washed with salt-containing hot water and then squeezed are picked in shochu (a low- class distilled spirit) and stored. The crystalline substance deposited on the surfaces of the leaves is extracted. Thereby, tartaric acrid can be obtained in an amount of about 15g from 1kg of the grape leaves or in an amount of about 12g from 1kg of the pinched young bunches.