Comparative study of the chemical composition and nutritive value of runner bean (Phaseolus coccineus) and of common bean (Phaseolus vulgaris)
Carlderón, E.; Velásquez, L.; Bressani, R.
Archivos Latinoamericanos de Nutricion 42(1): 64-71
Scarlet beans (Phaseolus coccineus) is an important food grain legume in the diet of rural populations living in the highlands of México, Guatemala and other countries of Latin America. The present study was conducted to obtain more chemical and nutritive data on this grain legume, because of its importance in agricultural production systems and due to the role it plays in rural diets. Ten samples were purchased in the highland markets of Guatemala, to compare their physical, chemical and nutritive characteristics with three samples of common beans (Phaseolus vulgaris). A sample of 10 kg was used for nutritional studies, fed alone and in mixtures with maize. The results indicated that P. coccineus has greater weight as compared to P. vulgaris (0.74 vs. 0.18 g) and are larger in size (0.60 vs. 0.14 cc/grain). Seed coat percentage was 10.2% for P. coccineus as compared to 9.0% for P. vulgaris. The cooking time was 231 minutes for P. coccineus and 180 minutes for common beans. Seed coat thickness and permeability are different when comparing P. coccineus with P. vulgaris, since at 24 hr soaking time, P. coccineus absorbed 80% of its water weight as compared to 100% for common beans. In chemical composition) small differences were found between P. coccineus and P. vulgaris. The first had slightly more ether extract, crude fiber and ash content than the second. Amino acid content among the six samples of P. coccineus was quite variable, but its pattern was rich in lysine and limiting in sulfur amino acids. Cooking time at 3 hr gave a higher NPR than when cooked at atmospheric pressure for 5 hr, with protein values relative to casein of 69.2 and 60.0%, respectively. P. coccineus protein quality was improved by methionine supplementation, and it appeared to be better digested than that of P. vulgaris. Mixtures of high protein quality were obtained with 15% P. coccineus and 85% maize while common beans and maize mixed in a 30 to 20 ratio showed maximum protein efficiency. The digestibility of the P. coccineus/maize mixtures was higher than that of common beans and maize.