Physical And Chemical Characteristics Of Common Bean Varieties

The common bean (Phaseolus vulgaris L.) is one of the most widely consumed legumes in the world, but nevertheless different varieties vary with respect to their physical and chemical aspects. This study evaluated the physical and chemical characteristics (color, hardness after cooking, water absorption capacity, cooking time, integrity of the beans after cooking, proximate composition and mineral composition) of the following varieties of the common bean: Carioca, IAPAR 81, Saracura, Juriti, Pérola, Colibri and IAPAR 31, all destined for both the internal Brazilian and external markets. The varieties studied had different proximate compositions and contents of the following minerals: K, Ca, N, Mg, S, Cu, Fe and Mn; but identical contents of P, Zn and B. The beans were classified as small in size. The Carioca variety showed the lowest values for L∗(41.29) and H∗ (57.22), and the highest values for a∗ (12.17), its beans being redder and darker than the others. The Saracura variety showed the lowest degree of hydration (95.70 g/100g), cooking time (22.67 min.) and whole beans after cooking (30%), while the Pérola variety showed the highest values for these same parameters, 106.77 g/100g, 43.67 min. And 82.16%, respectively. No correlation was observed between the calcium and magnesium contents of the beans and the hardness of the raw bean, degree of hydration during maceration, cooking time and integrity of the cooked beans. According to the characteristics studied, the Saracura variety is a good option for both industrial and domestic use.37275176

Effects of isoflavones on beany flavor and astringency os soymilk and cooked whole soybean grains.

Flavor is the main limiting factor affecting soybean acceptability in the Occidental countries. The purpose of this study was to determine the effetcs of isoflavones on soybean flavor. Differences in beany flavor and astringency of soymilk and cooked whole soybean grains, prepared with cultivars IAS 5 and BR-36 (136 and 54 mg of total isoflavones /100 g of sample, respectively) with pre-soaking and pre-heating of grains, were sensorially analyzed, by an unstructured category scale of ascending intensity. Differences in isoflavone contents for both soybean cultivars were maintained in the two products, despite the pre-treatments in the processing. Pre-soaking of grains intensified beany flavor in the soymilk, reducing the perception of astringency, which is caused by the aglucones that were developed in reduced amounts.The whole soybeans grains cooked under pressure (1.5 kgf/cm2 at 127°C) presented reduced levels of isoflavones malonyl-glucosides. Due to thermal instability, these compounds were converted to conjugated glucosides, genistin and daidzin. In the cooked whole soybean grains, no aglucones were formed and consequently it was not possible to detect differences in astringency. Results suggest that pre-heating of grains promote better flavor in soybean products