Temperature Dependence of Hydration Rate and Effect of Hydration on the Cooking Rate of Dry Legumes

Dry beans and peas are commercially hydrated for 12–16 hr at room temperature prior to processing. Hydration is usually considered necessary to decrease cooking times and increase the drained weight. However, the process also causes the loss of soluble solids and growth of microorganisms. The rate of moisture absorption of legumes was determined at temperatures ranging from 5–40°C by the method of weight gain. The times required to reach specified degrees of hydration were obtained. The z‐values for the rate of hydration were constant in only some of the products over the temperature interval studied. Hydration prior to cooking did not decrease significantly the cooking times. The z‐values for cooking of the hydrated beans and those cooked without prior hydration were similar. Hydration prior to cooking gave a significantly higher drained weight than without hydration for peas. Hydration had no effect on the drained weight of black beans.