[Flour of hard bean (Phaseolus vulgaris) in the preparation of bread]. / Harina de frijol endurecido (Phaseolus vulgaris L.) en la preparación de pan.

In order to utilize hardened beans, we proposed to find the method most indicated for the preparation of bean flour to determine their nutritional value, and to make bread of high industrial, nutritional quality, and good sensory characteristics, using blends of bean and wheat flours. Two types of flour were prepared, testing four soaking temperatures (22, 30, 40 and 50 degrees C) and two methods to remove the testa (under moist and dry conditions). At laboratory level, the dry testa removal method gave the best flour yields (mean = 85.8%) and the highest protein content (mean = 23.7%). Comparison between soaking temperature at 30 and 50 degrees C was not significant (alpha = 0.05). At pilot plant level, with soaking at 50 degrees C the flour yields were 58.0% for moist testa removal (H1) and 74.0% for dry removal (H2), with a protein content of 22.6% for H1 and 23.0% for H2. The H1 and H2 flours were added to wheat flour at 5, 10 and 15% for bread making. The addition of 5.0% gave breads with similar protein content and sensory characteristics to those of the control, wheat. A diet based on bean-flour bread resulted in greater weight gains than that with casein for gold hamsters. The study also demonstrated the importance of heat-treating of the bean flours, because when flour without previous heat treatment was administered, the animals lost weight and died. This effect was overcome by the process of baking the flours at 140 degrees C for four hours.

Harina de frijol endurecido (Phaseolus vulgaris L.) en la preparación de pan / Flour of hard bean (Phaseolus vulgaris) in the bread preparation

Con el propósito de utilizar el frijol endurecido, se propuso la búsqueda del método indicado para obtener harinas de frijol, determinar su valor nutritivo y elaborar panes con mezclas de harina de frijol y trigo de buena calidad industrial, nutricional, y sensorial. Se elaboraron dos tipos de harina, ensayándose cuatro temperaturas de remojo (22, 30, 40 y 50§C) y dos métodos de separación de testa (húmedo y seco). A nivel de laboratorio la separación de testa en seco proporcionó los mejores rendimientos harineros (x = 85.8%) y el más alto contenido proteínico (x = 23.7%). La comparación entre las temperaturas de remojo de 30 y 50§C respecto al rendimiento de harina no fueron significativas (* = 0.05). A nivel de planta piloto, con el remojo de 50§C los rendimientos harineros fueron de 58.0% para la separación de testa en húmedo (H1) y 74.0% para la separación en seco (H2), con porcentajes de proteína de 22.6% y 23.0% para H2. Para elaborar el pan de caja se adicionaron 5, 10 y 15% de harinas H1 y H2 a la de trigo, encontrando que la mezcla con 5.0% de H1 presentaba una buena calidad panadera, proteínica y sensorial, semejante al pan control, de ...

Phytic acid in stored common bean seeds (Phaseolus vulgaris L.).

Four varieties of common bean seeds stored at 4 degrees C, 80% relative humidity, for one to eight years showed no differences in proximal chemical composition, Seeds 5-6 years old absorbed more water than 1 to 4 year-old seeds. The cooking time required for five year-old seeds was 6 hours, while the fresh seeds needed 3/4-to-one hour cooking time. The most remarkable difference was in phytic acid content, which decreased 94% to 98% during long storage.

Denaturation by heat, sodium dodecyl sulphate and dithiothreitol of globulins and phaseolin from dry bean (Phaseolus vulgaris L.).

The electrophoretic pattern of the untreated common bean globulin cv. Flor de Mayo had 7 protein fractions ranging from 620 to 120 kilodaltons (kd). The last molecular weight corresponds to the monomeric form. One of the objectives of the present work was to establish a comparison among denaturation by heat, sodium dodecyl sulphate (SDS) and dithiothreitol (DTT). At pH 6.0, two bands were resistant to heat treatment, after SDS treatment of the untreated globulin several bands disappeared and two new bands with 26 and 15 kd appeared. DTT did not change the electrophoretic pattern, due to the small quantity of free SH groups in the globulin. At pH 6.0, phaseolin is partly resistant to heat denaturation due to aggregation in an acidic environment. Isoelectrofocusing (IEF) and SDS polyacrylamide gel electrophoresis (SDS-PAGE) separated phaseolin into 10 protein fractions. The hypothesis is that phaseolin or globulin aggregation is due to the charge difference of fractions.