Variedades de feijão e seus efeitos na qualidade protéica, na glicemia e nos lipídios sangüíneos em ratos

Abstract

Beans are important source of protein in the Brazilian staple food and may modulate the blood glucose and lipid levels. The objective of this study was to evaluate the protein quality and functional properties of varieties of beans. Seven groups (n = 6) of weaning rats were used for the bean protein quality analysis. The first group was fed protein-free diet for 14 days, and the remaining were fed diets with 9 to 10% protein provided by either casein or one of the 5 varieties of beans (Ouro Branco, Pérola, BRS Radiante, Diamante Negro, and Talismã). In a further study, 4 groups (n = 10) of adult rats were fed diets containing either casein or "Ouro Branco", "Diamante Negro", and "Talismã" beans (30g.100g-1diet), for 28 days. "Ouro Branco", white beans, showed higher relative Protein Efficiency Ratio (rPER = 61.18%) than the other varieties, and the "BRSRadiante", brown beans, showed the lowest value (rPER = 44.60%). In terms of Net Protein Ratio (NPR) and digestibility, no difference was observed between the varieties studied (p > 0.05), varying from 67.05 to 78.19%, and 78.70 to 84.88%, respectively. "Diamante Negro", black and brown beans, and the "Talismã" beans showed 30 and 26% reduction of blood glucose, respectively, compared to the casein group but not at significant levels. No difference (p > 0.05) was observed between the varieties in terms of serum cholesterol and triacylglycerol levels. This indicates that the nutritional and functional demands of the population may be supplied by different varieties of beans.