Cooking time of dry bean grains according to water type

Beans are an important source of protein and minerals, but they are underutilized because of the long hydration and cooking times required for the digestibility by humans. The aim of this work was to evaluate the water quality in the cooking time of grains of common beans using ultra-pure, distilled, tap and, mineral water. The grains of the BRS-Valente cultivar were hydrated 21 hours in ultra-pure water. In intervals of one hour they were cooked in distilled water and tap water until the last hydration time. Only the beans hydrated for 6 hours were cooked in ultra-pure, distilled, tap and mineral water. The increase in the hydration time provided a decrease in the cooking time, but the higher correlation (around-0.9) was negative because the decrease of cooking time in the first two hours of hydration. Thus, the general correlation did not explain the trend of the results, but rather the whole set of analysis, through the segmented linear regression. The conclusion was that the fast hydration time was an indicative of the low cooking time for BRS-Valente, since the grain showed 69% of hydration in two hours of hydration. The use of ultra-pure water throughout the cooking process provided normal level of cooking resistance (23 to 30 minutes), tap water was different from all waters and provided average resistance level of cooking (+/- 37 minutes), while the mineral water showed very high (>300 minutes) cooking time.