Roasting

Though most legumes are cooked in liquid to soften their starch and cell walls, a few are parched in dry heat to create a crisp texture. Peanuts are the most commonly roasted of the legumes, thanks to their nut-like oil content and relatively tender cotyledons. Other beans with lower oil contents, notably soybeans and chickpeas, are also roasted to make a nut-like seed. Because their cotyledons are harder, they’re soaked in water first, then roasted. The initial high temperature and moisture soften the cotyledon cell walls and starch granules; continued roasting evaporates most of the water to give a crisp rather than hard texture. The roasting can be done in a hot pan or oven, or—as is done in Asia—in sand that has been heated to 500–600°F/ 250–300°C. In India, for example, chickpeas are heated to around 180°F/80°C, moistened with water, rested for some hours, then roasted in hot sand so that they puff and the seed coat can be rubbed off.