Influence of germination on the nutritional quality of Phaseolus vulgaris and Cajanus cajan

Abstract

Germination is a method that can modify the presence of nutrients and antinutrients in legume seeds. In this study, the changes in trypsin inhibitors activity (TIA), phytic acid, tannins, ascorbic acid, thiamine, protein digestibility and minerals in germinated black beans ( Phaseolus vulgaris L.), white beans ( Phaseolus vulgaris L.) and pigeon beans ( Cajanus cajan L. Millsp) were evaluated. The ungerminated grains were analysed as control. A significant decrease in the content of TIA of pigeon beans (19.2%), white beans (52.5%) and black beans (25%) was observed. The reduction of phytic acid was more than 40% for the three grains germinated; for the tannins, the reduction was of 14.3% for pigeon beans, 19% for black beans and 36.2% for white beans. Germination increased the protein digestibility in a 2–4% range, and also increased the ascorbic acid by 300% for white beans, by 33% for black beans and by 208% for pigeon beans. The thiamine content increased more than 26.7%. Germination affected the mineral content erratically, depending more on the grain and the type of mineral. These variations in the content of nutrients and antinutrients of the germinated grains are attributed to the joint effect of the germination and previous soaking the grains were subjected to.