Nutritional assessment of protein from beans (Phaseolus vulgaris L) processed at different pH values, in growing rats

Abstract

The effect of the commonly used processing techniques of soaking (at different pH values) and cooking on the digestive and metabolic utilisation of protein from common beans (Phaseolus vulgaris L) in growing rats was studied. Before the cooking step, beans were soaked in solutions of pH 2.6, 5.3 or 8.4. Analyses of beans soaked at moderately acid pH (5.3) showed a signi®cant increase in essential amino acids, especially cysteine. Food intake and growth indices were also dependent on pH. All indices were better in animals fed with beans soaked in a basic pH solution than when an acid soaking solution was used. In contrast with the ®ndings expected on the basis of the chemical analysis of protein composition of the food, the worst results for food intake and growth were found in rats fed with beans soaked at pH 5.3. There were no signi®cant differences in apparent digestibility coef®cient between different groups of animals. The highest metabolic utilisation of protein (balance) was found in animals fed with beans soaked in a basic solution; however, the values were insuf®cient to account for the faster rate of growth in this group. The better growth rate was probably due to the improved utilisation of carbohydrates in beans soaked in the basic pH (8.4) solution.

Nutritional Evaluation of Pea (Pisum sativum L.) Protein Diets after Mild Hydrothermal Treatment and with and without Added Phytase

“…Digestive Utilization of Protein. The rate of digestive utilization of protein in peas is high, similar to that found for faba beans () and much higher than that of lentils, chickpeas, and beans ( − ). The improvement in the digestive utilization of protein (83.5−86.8%) by the application of mild hydrothermal treatment is attributed to the diminution in TIA (70%) and in phytic acid (78%).…”