Kelp seaweed, usually sold in dried strips. Kelp has the delicious taste characteristic of glutamic acid. The white powder on the surface of kelp contains a flavour component, so it shouldn't be wiped off. Kelp is rich in potassium, calcium, iodine and carotene. It also contains amino acids that help lower blood pressure. Choose blackish kelp that is lustrous and well-dried. This seaweed is used to make dashi and also appears in nabe dishes and wrapped around fish, which are then simmered. Kelp seaweed is used to season stocks, rice and vegetables. It is also cut into strips and made into little baskets which are fried and served with vegetables. To cook it, simply wipe a piece with a cloth and put it into 1 litre (2 pints) of water; bring it slowly to the boil and then simmer for about 5 minutes. Remove the kombu and keep for cooking with other ingredients. The stock may be used to add to soups, broths or stews. The konbu may be cut up and cooked with root vegetables seasoned with soy sauce or cooked with beans.