title: [Chemical composition and evaluation of the protein quality of beans in adult humans by the short-term nitrogen balance method].
abstract: Three varieties of common beans were chemically analyzed and their protein quality was evaluated in 12 human male adult subjects by the short-term nitrogen balance method. Chemical analyses were performed for both raw and cooked grains. Cooking reduced the trypsin inhibitors in 28 to 73%, hemagglutinins, 100%, tannins as acid tannic equivalents, 9 to 72%, and 55 to 75% as catequin equivalents, and alkali-soluble nitrogen in 65%. Red and black beans contained more residual trypsin inhibitors and tannins than white beans, while the latter contained more alkali-soluble nitrogen. Although cooked colored beans had more antinutritional factors that affect protein digestibility, their protein quality was similar to that of white beans. This could be explained by the fact that the amino acid composition and/or balance of red and black beans absorbed nitrogen is better than that of white beans, so that the final nutritional value will be determined by the sum of interactions between all factors. In this study, each of the three varieties presented at least one protein quality depressor in higher concentration than the other two varieties. Therefore, the overall differences found between treatments and residual effect, were small or non existent, while significant differences (p greater than 0.05) were found between subjects and nitrogen balance periods. A level of 0.65 g of bean protein/kg/day was not enough to maintain nitrogen balance in subjects fed a diet where beans were the only protein source. According to calculations, 0.9-1.0 g of bean protein/kg/day are necessary for nitrogen balance in male adults, and 1.2-1.3 g of protein bean would be the recommendation for a normal population.
mesh_terms: D000328:Adult; D004032:Diet; D007887:Fabaceae; D005504:Food Analysis; D005511:Food Handling; D006388:Hemagglutinins / Q000032:analysis; D006801:Humans; D047348:Hydrolyzable Tannins / Q000032:analysis; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D009753:Nutritive Value; D014674:Plant Proteins, Dietary; D010946:Plants, Medicinal; D014361:Trypsin Inhibitors / Q000032:analysis
chemical_list: D006388:Hemagglutinins; D047348:Hydrolyzable Tannins; D014674:Plant Proteins, Dietary; D014361:Trypsin Inhibitors; D009584:Nitrogen
vernacular_title: Composición química y evaluación de la calidad de la proteína del frijol en humanos adultos por el método de balance nitrogenado de corto tiempo]