nagaimo

Nagaimo is a tuber from the Dioscorea genus that is widely used in East Asian cuisines, especially in Japan. In Japanese usage, nagaimo typically refers to the edible root of Dioscorea polystachya var. esculenta, commonly called Chinese yam or Japanese yam outside Japan. Other Dioscorea species produce similar tubers and are sometimes sold under the same name in various markets.

The tuber is long and cylindrical, with brownish skin and white flesh. It is moist and starchy, and remains pale when peeled. When grated or finely sliced, nagaimo releases a viscous, mucilaginous liquid, giving a slippery texture that is valued in certain preparations.

Culinary uses vary. Nagaimo can be eaten raw or lightly cooked. Grated nagaimo, known in Japan as tororo, is a classic topping for rice or noodles and can thicken soups or sauces. It is also sliced, julienned, or mashed and appears in tempura, nimono, and sushi preparations. The flavor is mild and slightly sweet, allowing it to pair well with soy sauce, dashi, citrus, and other seasonings.

Nutritionally, nagaimo provides primarily carbohydrates with small amounts of protein and minerals such as potassium. Fresh tubers should be stored in a cool, dry place; once peeled, they keep for a few days in the refrigerator. Grated nagaimo can discolor when exposed to air and should be used promptly. Some individuals may experience throat irritation or allergies; handling with care is advised.