Glossary - Ingredients

Kuwai / Arrowhead Tuber

An auspicious vegetable identifiable by its distinctive shape with a large sprout growing from a round, blue tuber-root

What are kuwai?

Kuwai (くわい in Japanese) grow in the mud underwater, similar to rice paddies. The edible part of the kuwai is the round root that grows underwater. The large sprouts that grow from them are considered to bring good luck and are therefore seen as indispensable in New Year's cuisine. They have a soft texture and a bitter, sweet taste that lingers when eaten. In addition to being simmered, they can be deep-fried, stewed in cream, or thinly sliced and deep-fried as kuwai chips.

Nutrition facts

Kuwai is primarily comprised of starch. It is also rich in iron, zinc, niacin, and folic acid. Kuwai has one of the highest levels of biotin, a B vitamin, amongst vegetables. Biotin helps maintain healthy skin and other organs, strengthens nails, relieves muscle pain, and helps in recovery from fatigue.
Kuwai's dietary fiber contains soluble and insoluble dietary fiber in a 1:3 ratio, which is expected to help regulate the intestines. It also contains a lot of potassium, which helps to expel excess salt from the body and is therefore useful in preventing high blood pressure.
Kuwai contains high amounts of zinc, so its absorption rate increases when eaten with foods that are rich in animal protein and vitamin C.

Storage to prevent food loss

Kuwai can be stored in the refrigerator for 3-4 days by soaking them in water or wrapping them in plastic wrap.

Trivia

After peeling kuwai, soak them in water to remove the astringency before eating. Fukuyama City in Hiroshima Prefecture is the top producer of kuwai in Japan, boasting a share of about 70% for the whole country.