Kombu (a member of the Kelp family) is probably most well known for the unique effect it has on the taste buds, that which the Japanese call Umami and what we know in the west as our 5th flavour or simply savoury.
Kombu is a very versatile sea green (brown!) which adds vitamins and minerals to any dish. It is used to make broths and serves as a base ingredient in stocks.
It has a special use for cooking dried beans or pulses. When adding a strip of Kombu to the cooking process, it helps make beans much more digestible by breaking down the enzymes that cause the gassy feeling when eating beans. It also adds a subtle background flavour, by some described as tasting slightly bacony.