Carrageenan, Alginates, Gellan

Experimentally minded cooks are exploring a number of other unusual carbohydrate gelling agents, some traditional and some not. Carrageenan, from certain red algae, has long been used in China to gel stews and flavored liquids, and in Ireland to make a kind of milk pudding. Purified fractions of crude carrageenan produce gels with a range of textures, from brittle to elastic. Alginates come from a number of brown seaweeds, and form gels only in the presence of calcium (in milk and cream, for example). Inventive cooks have taken advantage of this to make small flavored spheres and threads: they prepare a calcium-free alginate solution of the desired flavor and color, and then drip or inject it into a calcium solution, where it immediately gels. Gellan, an industrial discovery, is a carbohydrate secreted by a bacterium, and in the presence of salts or acid forms very clear gels that release their flavor well.