Soaking beans: alternative to improve nutritional value

Abstract

Bean protein is deficient in sulfur amino acids and has reduced digestibility, mainly due to the poliphenols and phytates present in the grain. The soaking process may reduce the content of these substances and, thus improving protein digestibility. The purpose of this study was to investigate the effect of the soaking process on bean protein quality. Common beans (cv Carioca) were soaked before cooking over two periods of time (4 hours and 12 hours), in the proportion of 1:3 (grain:water) and another bean sample was cooked without soaking. An experiment with Wistar rats was carried out and bean protein quality was estimated by means of Net Protein Ratio (NPR) and Net Protein Utilization (NPU). Soaking process during 4 h was sufficient to reduce in a half the bean cooking time. Soaking for 12 hours improved the protein quality of the beans. Thus, the soaking process may improve the protein intake of poor community.