Like kombu, kelp is used in soups and stews, stir-fried with vegetables, or cooked with beans or grains. It cooks quickly and dissolves in longer-cooking dishes. It contains a natural glutamic acid, a tenderizer that helps beans cook quickly and makes them more digestible. It also contains alginic acid, a substance used as a thickening and stabilizing agent in food production. Kelp can be pre-soaked or added dry to foods with liquids. Kelp absorbs up to five times its weight in liquid.