RESUMO
Se estudiaron las características químicas, físicas, antifisiológicas y de calidad biológica de la proteína de tres variedades (blanco, café y negro) de frijol tépari (Phaseolus acutifolius). Se determinó su composición proximal, patrones de absorción de agua, dureza del grano, contenido de taninos, inhibidores de tripsina y presencia de lectinas. Los frijoles fueron también sometidos a estudios de calorimetría diferencial de barrido. El valor nutritivo de sus proteínas fue establecido a través de la razón de eficiencia proteínica (PER) y digestibilidad aparente de proteína (DAP). Se encontró que el contenido proteínico del frijol es alto (25%). El frijos blanco tuvo una mayor capacidad de absorción de agua y presentó menor dureza el grano en comparación con las otras variedades (P < 0.05). El frijol negro reveló una menor energía de gelatinización de su almidón y un mayor tiempo de cocción en comparación con el frijol blanco y café. El contenido de taninos de las tres variedades fue bajo, particularmente el frijol blanco. Las actividades de inhibidores de tripsina y capacidad aglutinante de lectinas fueron relativamente altas en el frijol crudo, pero desaparecieron casi totalmente con la cocción. La calidad biológica de las proteínas de tépari demostró ser superior a la del frijol común cosechado bajo las mismas condiciones, siendo esto más evidente en el caso del frijol blanco (PER = 1.48 respecto a 1.23 del frijol pinto). Se concluye que el frijol tépari constituye una buena fuente...
Assuntos
Dieta , Glycine max/análise , Manipulação de Alimentos , Valor Nutritivo , Proteínas de Vegetais Comestíveis/análise , Análise de Variância , Calorimetria , Ratos Sprague-DawleyRESUMO
Em amostras de amendoim cru e feijäo coletadas em estabelecimentos comerciais de Belo Horizonte, Minas Gerais, Brasil, durante o ano de 1984, foram verificados os níveis de aflatoxinas B1 e G1 por intermédio de cromatografia em camada delgada. Os teores de aflatoxina B1 encontrados em amendoim cru foram comparados com os encontrados em 1983. Em aproximadamente 30 por cento das amostras analisadas o teor de aflatoxina B1 foi superior ao valor máximo tolerado pela legislaçäo brasileira, porcentagem essa inferior à encontrada em 1983. Em nenhuma das amostras de feijäo foi detectada a presença de aflatoxina.
Assuntos
Aflatoxinas/análise , Arachis/análise , Glycine max/análise , Contaminação de Alimentos/análise , Qualidade dos AlimentosRESUMO
Laboratory conditions were first investigated to determine are optimum processing parameters for the preparation of a protein isolate from the ground, defatted, commercial flakes of Lupinus mutabilis. The extraction variables were: pH (2-10); solvent to lupine ratio (5:1 to 40:1); temperature (28 degrees C - 60 degrees C) and time (10-50 min). The isoelectric point of the lupine protein was found to be pH 4.5 with a protein solubility higher than 80% above pH 8.0. Using 70-100 mesh, ground defatted flakes, and extracting at pH 8.7 for 60 min, a protein isolate was obtained on acidification to pH 4.5 which was 99.8 protein (dry basis), compared to 55.25% protein for the original material. This protein isolate represented 32% of the initial material and 57.6% of the initial nitrogen. When making pilot plant assays we found that the yield of protein isolate decreased to 20.4% of the original material and 36.4% of the initial nitrogen. The protein efficiency ratio for the protein isolate was 2.15 when supplemented with methionine, and had a digestibility of 89.33
Assuntos
Manipulação de Alimentos , Proteínas de Plantas , Sementes , Aminoácidos/análise , Caseínas/análise , Concentração de Íons de Hidrogênio , Metionina/análise , Projetos Piloto , Proteínas de Plantas/isolamento & purificação , Glycine max/análise , TemperaturaRESUMO
Ten soybean varieties with colored seed coats were evaluated in Jaboticabal, with the objective of obtaining information as to color preference in the direct use of soybeans in human consumption. The above-mentioned material showed good adaptation to the local environmental conditions: plant cycles were smaller than the Santa Rosa (121 days), varying from 107 to 119 days, in spite of the fact that some varieties started blooming later than Santa Rosa. All materials are within the minimum standards for local planting; however, some of them showed a lodging problem, and all varieties are susceptible to bacterial pustule. They have smaller seeds than Santa Rosa, and in relation to yield, varieties as the NC-55, Aksarben 1S (Black), Aksarben 1S (Brown) and Chi kei 13 did not statistically differ from the Santa Rosa. Protein content showed a variability of 37.90 to 43.90% and oil varied from 14.72 to 21.34%. Methionine content was between the known limits (0.907 to 1.644 g/16 g N), but lysine was higher than any reported data (7.584, to 10.877 g/16g N). The Tanner, Chi kei 13 and Chi kei 15 presented a high percentage of hard beans. This fact had a positive influence on the seed hydration characteristics, but their experimental cooking times were very low, varying from 51 and-a-half to 122 minutes. The term "hydration time" is being introduced here, which is defined as the time, in hours, required for a seed to double up its weight when submerged in water.
Assuntos
Aminoácidos/análise , Glycine max , Proteínas de Plantas/análise , Bactérias , Cromatografia Líquida , Cor , Tecnologia de Alimentos , Temperatura Alta , Vírus do Mosaico , Valor Nutritivo , Sementes , Glycine max/análise , Glycine max/microbiologiaRESUMO
Preterm infants with birth weights between 1,001 and 1,600 gm were randomly assigned at one week of age to three groups and fed a standard milk-based formula, the same formula with iron, or a soy-based formula with iron. Hematologic values and selenium status were then studied prospectively for five weeks. Rates of decline in hematocrit and hemoglobin did not differ significantly among the three groups and did not correlate with red cell selenium values or glutathione peroxidase activity. Attainment of vitamin E sufficiency was variable among the infants, with no significant intergroup differences. Plasma selenium concentrations did not change significantly, but plasma glutathione peroxidase activity declined consistently in all three groups. Under the conditions of this study, iron at a concentration of 12 mg/L of infant formula did not accelerate hemolysis; nor was there evidence of a direct association between selenium values and early anemia of prematurity.