Common Bean Leaves as a Source of Dietary Iron: Functional Test in an Iron-Deficient Rat Model.

Recent findings made by our group indicate that the iron content in Phaseolus vulgaris leaves is at least four times greater than in grains therefore, we evaluated the effect of supplementation with bean leaf (iron content of 275 mg/kg on a dry basis) in iron-deficient rats. Anemia was induced by feeding rats with an iron-deficient diet (IDD) for 11 days and iron-recovery diets were subsequently tested for 14 days using a normal diet, a 10 % bean leaf-supplemented IDD (BLSD) or a ferrous sulfate-supplemented IDD. Decreased levels of leukocytes (64 %), erythrocytes (30 %), lymphocytes (62 %), granulocytes (72 %), hematocrit (34 %), hemoglobin (35 %), and ferritin (34 %) were observed in the iron-deficient rats compared to the control rats. BLSD supplementation showed the highest recovery values relative to those recorded for control rats: leukocytes (40 %), erythrocytes (24 %), lymphocytes (33 %), granulocytes (88 %), hematocrit (17 %), and hemoglobin (18 %), suggesting that common bean leaves could be a good source of bioavailable iron with possible immunomodulatory effects.

Cooked common beans (Phaseolus vulgaris L.) modulate renal genes in streptozotocin-induced diabetic rats.

Food consumption with different bioactive compounds could reduce the risk of diabetic complications. This study was designed to evaluate the effect of cooked common beans on differentially expressed genes in whole kidney homogenates of streptozotocin-induced diabetic rats. After 4weeks of treatment with a cooked bean supplemented (10%) diet, animals fed with Flor de Mayo bean (FMB) exerted the greatest protective effect, since they presented the lowest blood glucose levels, consistent with an increase in blood insulin levels, a decrease in urine albumin and urea levels and an increase in creatinine clearance (P≤.05). Regarding the gene expression of kidneys evaluated using expressed sequence tag, consumption of cooked beans improved the expression of Glu1, Cps1, Ipmk, Cacna1c, Camk1, Pdhb, Ptbp3 and Pim1, which are related to the elimination of ammonium groups, the regulation of inflammatory and oxidative response, as well as cell signaling and apoptosis. In addition, the beneficial effects observed were not related to their polyphenolic and saponin profile, suggesting the activity of other bioactive compounds or the synergistic interaction of these compounds. These results suggest that the consumption of cooked common beans (FMB) might be used as an alternative for the regulation of genes related to renal alterations.

Cooked common beans (Phaseolus vulgaris) protect against ß-cell damage in streptozotocin-induced diabetic rats.

Diabetes is a disease characterized by a hyperglycemic stage that leads to a chronic inflammatory state. We evaluated the in vivo effect of a diet supplemented with 25 % cooked black bean cultivar Negro 8025 (N8025) flour in streptozotocin-induced diabetic rats. The effect was assessed before (preventive-treatment) and after (treatment) the onset of diabetes. There is a significant decrease of total phenolic, tannins and anthocyanins content after cooking, and the concentration of most of the single phenols analyzed are only slightly decreased. The treatment group showed a significant reduction of glucose (22.8 %), triglycerides (21.9 %), total cholesterol (29.9 %) and LDL (56.1 %) that correlates with a protection of pancreatic ß-cells. The diet with N8025 flour before the induction of diabetes did not exert a protective effect (glucose levels are similar to the diabetic control) but they have low levels of total cholesterol (47.5 %) and LDL (56.1 %). The preventive-treatment group did not inhibit the increase of TNF-α and IL-1ß, whereas the treatment group did, compared to the diabetic control. Therefore, N8025 bean supplementation can be recommended to control diabetes.

Chemical evaluation, antioxidant capacity, and consumer acceptance of several oak infusions.

As part of an ongoing screening on natural products, 4 oak leaves were analyzed as potential nutraceutical beverages. The phenolic composition, antioxidant capacity, and sensory preferences of leaves infusions from Quercus resinosa, Q. sideroxyla, Q. eduadii, and Q. durifolia in comparison with 2 commercial green teas were investigated. Herbal infusions from oak leaves and Green teas (1%, 80 °C, 10 min) were evaluated for total polyphenol content (TPC), total flavonoid content (TFC), HPLC analysis, trolox equivalent antioxidant capacity (TEAC), oxygen radical absorbance capacity (ORAC), soluble solids, pH, color, and consumer preference analysis. Q. resinosa leaves infusions have shown the highest TPC, TEAC, and ORAC values but they have attained the lowest preference score. Quercus leaves infusions with higher content of gallic acid and catechins showed best antioxidant capacity but lower consumer preference.

Non-digestible fraction of cooked bean (Phaseolus vulgaris L.) cultivar Bayo Madero suppresses colonic aberrant crypt foci in azoxymethane-induced rats.

The non-digestible fraction (NDF) of common bean (Phaseolus vulgaris L.) cultivar Bayo Madero was evaluated for its chemopreventive effect on azoxymethane (AOM) induced aberrant crypt foci (ACF) in rats. Diets containing cooked beans (CB) or its non-digestible fraction (NDF) were fed to 72 male rats after 2 azoxymethane injections (15 mg kg(-1) of body weight once a week for 2 weeks). ACF number, short chain fatty acids (SCFA) and ß-glucuronidase activity were measured in colon sections from rats sacrificed 7 weeks after the last AOM injection. Food intake and weight gain of rats were unaffected by CB and NDF. CB and NDF suppressed the AOM-induced formation of ACF (0.8 and 1.5 ACF/distal zone, respectively vs. 6.6 ACF/distal zone based on methylene blue stain) and lowered ß-glucuronidase activity in cecal, colonic and fecal content compared to AOM group. SCFA production was not significantly different among fecal, cecal and colonic content. These results indicate that CB and NDF from Bayo Madero provide direct chemoprotection against early stage of azoxymethane (AOM)-induced colon cancer in rats.

Hábitos preferenciales de los consumidores de frijol común (Phaseolus vulgaris L) en México / Preferential habits of consumers of common bean (Phaseolus vulgaris L) in Mexico

El conocimiento de los hábitos preferenciales de los consumidores de frijol es fundamental para definir los objetos en los programas de mejoramiento genético y para diseñar las estrategias de mercadeo en una región o país determinados. El presente trabajo se basó en la aplicación de 1514 encuestas a consumidores de frijol de 14 entidades federativas de la República Mexicana. Para la interpretación de los resultados el país se dividió en cuatro regiones: Noroeste, Centro y Sur. En la región Noroeste el 98 por ciento de los encuestados consume frijol "Azufrado" (amarillo azufre); en el Noreste el 70 por ciento concume "Pinto" (beige con motas cafés) y "Bayo" (Beige); en la zona Sur el 90 por ciento consume frijol "Negro", mientras que en la zona Centro se consume todas las clases comerciales. Se detectó que dentro de cada clase comercial existen preferencias específicas en relación al tamaño y brillantez del grano; sin embargo, en la clase comercial Negro los consumidores prefieren el grano de testa opaca y tamaño de 18-22/100 semillas mientras que en la clase "Flor de Mayo" (beige con motas rosas) los consumidores prefieren grano de testa brillante y tamaño de 30-35/100 semillas. La principal característica que utilizan los consumidores para definir sus preferencias es el tiempo de cocción y el sabor. Se detectó que entre los consumidores de frijol los hábitos preferenciales están muy arraigadas pues el 70 por ciento declaró no estar dispuesto a cambiar el frijol de su preferencia aún cuando la clase alternativa fuese más barata. Por otro lado, los consumidores normalmente no remojan el grano en agua ni agregan sal al inicio del proceso de cocción para no afectar el sabor y apariencia del frijol. Estos resultados fueron confirmados con pruebas sensoriales. En el presente trabajo también se discuten aspectos relacionados con formas de procesamiento y consumo y algunos aspectos de mercadeo del grano de frijol

Efecto de la localidad de siembra sobre la aceptación sensorial y otras características nutricionales y de calidad del grano en frijol común (Phaseolus vulgaris L) / Effect of growing location on sensory properties and nutritional characteristics of black beans (Phaseolus vulgaris L)

Se llevó a cabo el análisis de la evaluación sensorial en función al sabor y aceptación general del frijol entero cocido, en cinco variedades de frijol sembrado en seis localidades de México. Se determinó el tiempo de cocción con cocedores tipo Mattson. Se cuantificó el contenido de taninos y la actividad específica de lectinas. Se observaron diferencias estadísticas significativas (p<0.05) en los estudios de evaluación sensorial de los materiales provenientes de Calera específicamente en las variedades que sufrieron heladas y bajas temperaturas. Características como el sabor, color, espesor de caldo e integridad del grano resultaron de interés a los jueces. Se encontraron diferencias significativas (p<0.05) en el tiempo de cocción entre genotipos y entre localidades, observándose un efecto importante en esta determinación causado por las heladas. No se encontró alguna correlación entre el contenido de Ca y Mg en el suelo y el tiempo de cocción de frijol. La concentración de taninos mostró diferencias significativas (p<0.05) para los genotipos y las localidades. La actividad específica de lectinas no mostró ninguna diferencia entre genotipos pero si entre localidades, sin efecto aparente por las bajas temperaturas