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A conventional breeding program was established to transfer the bacterial phytoene synthase transgene-crtB-from a transgenic, white-rooted cassava to yellow-rooted cassava plants carrying the endogenous phytoene synthase alleles named psy2-y 1 and/or psy2-y 2. Combining endogenous phytoene synthase enzymes (PSYs) with CRTB in a single cassava plant would allow the molecular dissection of individual allele contributions to carotenoid synthesis and/or accumulation in cassava roots. The simultaneous expression of the crtB transgene and psy2-y 2 in individuals planted in the field coincided with higher total, HPLC-quantified carotenoid content in roots, although the variability among replications (plants) precluded the detection of statistically significant differences. Nevertheless, the highest total carotenoid content in roots within a family coincided with one individual of the F1 progeny carrying both psy2-y 2 and crtB genes. The results also indicated the presence of at least one more key gene-different from psy or crtB-which too is necessary for the synthesis and/or accumulation of Pro-Vitamin A carotenoids in cassava roots.

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An antioxidant is a compound capable of inhibiting molecular oxidation and therefore of protecting biological molecules from reactive oxygen species or free radicals. Antioxidants can be synthesized by the body or obtained from a diet containing fruit, such as soursop. The aim of this project was to review the literature on antioxidant activity of the soursop and compounds that might be responsible for this activity. From the analysis of fourteen studies, we found that in most cases soursop did not contain high activity or concentration of antioxidants in fresh or frozen pulp, in comparison with highly consumed fruits in Colombia. The leaves, as well as the juice and wine from the plant, do not contain high activity or concentration of antioxidants. In-depth characterization of antioxidant activity and compounds in soursop is lacking; additional studies are required to identify the mechanisms of action of the compounds present in the whole fruit (peel and seed) for different varieties of this tropical fruit.

Los compuestos antioxidantes están en la capacidad de inhibir la oxidación de moléculas y por lo tanto actuar como protectores de moléculas biológicas contra especies reactivas de oxígeno o radicales libres. Muchos antioxidantes pueden ser sintetizados en el cuerpo u obtenidos a partir de una dieta basada en frutas, como la guanábana. El propósito del presente trabajo fue revisar las principales investigaciones relacionadas con el estudio de la capacidad antioxidante de la guanábana y los compuestos presentes que le otorgan dicha propiedad. A partir del análisis de catorce investigaciones halladas sobre el tema, se encontró que en la mayoría de los casos la guanábana no contiene concentraciones elevadas de actividad o compuestos antioxidantes en su pulpa fresca o congelada comparada con frutos de mayor consumo en Colombia. Sus hojas, al igual que sus jugos y vinos, no contienen concentraciones elevadas de actividad o compuestos antioxidantes. Sin embargo, el tema de investigación de compuestos antioxidantes en guanábana se ha realizado con poca profundidad, hace falta estudios adicionales con métodos que logren la identificación de los mecanismos de acción de los compuestos presentes en el fruto completo (cáscara y semilla) de las diferentes variedades que se conocen de este fruto tropical.

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En este trabajo se valida un método espectrofotométrico para la determinación de glucósidos cianogénicos (CGs) de acuerdo a los requerimientos de IUPAC y ICH para nuevos métodos. El método demuestra una buena linealidad en el rango de 0,1-0,88 μgg-1 de ácido cianhídrico (HCN). La exactitud del método está entre 95,2 y 96,4%. La precisión del método reflejada como la desviación estándar relativa de los replicados es menor al 12%. El método se compara con el método más usado para la detección de CGs en raíces de yuca, el método de Essers et al. Ambos métodos se usan en la cuantificación de CGs en productos comerciales de yuca. El nuevo método es una herramienta útil y confiable para monitorear los niveles de CGs en productos comerciales de yuca.

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Foliar extracts (FEs) are an alternative to address food and nutrition insecurity. FEs and leaves of cassava, bean, sweet potato and alfalfa were evaluated for nutrient and antinutrient composition and in vitro nutrient bioavailability. Bean FE had a high average ± (SD) iron concentration (1006 ± 8.49 mg/kg), as did cassava FE for zinc (110.1 ± 6.72 mg/kg) and soluble protein (34.23 ± 3.81 g/kg) concentration. For the cassava, bean and alfalfa FEs in vitro protein digestibility was greater than 71.18 percent; in vitro iron dialyzability was less than 2.29 percent; the phytate:zinc molar ratio was less than 0.08, and the in vitro all-trans-β-carotene bioavailability was greater than 23.85 percent. These values suggest a high protein, zinc and all-trans- β -carotene bioavailability and a low iron bioavailability. FEs can be a nutritious alternative for those countries with low dietary diversity.

Los extractos foliares (EF) son utilizados como complemento nutricional en países como Nicaragua y Tanzania. Se evaluaron hojas y EF de yuca, fríjol, batata y alfalfa, y se cuantificó los componentes nutricionales, antinutricionales y biodisponibilidad por métodos in vitro. En promedio (DE), el EF de fríjol tiene una elevada concentración de hierro (1006,23 (8,49) mg/kg); el EF de yuca tiene alta concentración de zinc (110,65 (6,72) mg/ kg) y proteína soluble (34,23 (3,81) g/kg). Así mismo, la digestibilidad in vitro de proteína en los EFs de yuca, fríjol y alfalfa fueron superiores a 71,18 por ciento; hierro dializable in vitro menor a 2,29 por ciento; la relación molar fitato:zinc inferior a 0,08 y la bioaccesibilidad all-trans-β -caroteno superior a 23,85 por ciento. Estos valores sugieren una alta asimilación de proteína, zinc y all-trans-β -caroteno, y una baja asimilabilidad de hierro. Los EFs pueden ser una alternativa nutricional en la alimentación en países que carecen de diversificación alimentaria.

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Objetivo. Investigar si el maíz QPM (con más triptófano y lisina) presentaba mejor calidad proteica que el maíz común (MC) utilizándolo en preparaciones colombianas. Material y métodos. Entre 2008 y 2009, en el CIAT, Palmira, Colombia, se evaluó la concentración de triptófano, proteína soluble (PS) y digestibilidad in vitro de proteína (DP) en 10 recetas, preparadas con QPM o MC. Resultados. El triptófano osciló entre 0.011 y 0.072 por ciento para MC y 0.012 y 0.107 por ciento para QPM. Las recetas de QPM presentaron mayor o igual concentración de triptófano que las recetas de MC. PS osciló entre 2.359 y 14.783 g/kg para MC, y 3.339 y 16.839 g/kg para QPM. Las recetas de QPM, exceptuando una, presentaron mayor o igual concentración de PS. DP estuvo entre 75 y 84 por ciento para ambos maíces. Sólo cuatro recetas presentaron diferencia de DP entre QPM y MC. Conclusiones. Las recetas de maíz QPM son de mejor calidad proteica.

Objective. Ten typical recipes from southwestern Colombia were evaluated at CIAT in Palmira, Colombia between 2008 and 2009. Material and Methods. The recipes were prepared in a traditional manner, using quality protein maize (QPM, with more tryptophan and lysine) or common maize (CM); each of these was either fresh kernel or dry grain, or white or yellow maize, per the recipe. The two types of maize were compared for their protein quality. Results. Tryptophan concentrations were 0.011-0.072 percent and 0.012-0.107 percent for CM and QPM, respectively. Tryptophan values for QPM recipes were greater than or equal to those for CM recipes. Soluble protein ranged from 2.359-14.783 g/kg for CM and 3.339-16.839 g/kg for QPM. Except for one recipe, soluble protein in QPM recipes was greater or equal to that of CM recipes. In vitro protein digestibility was 75-84 percent for recipes prepared with both maize types. Only four recipes had a statistically significant difference between QPM and CM with regard to digestibility. Conclusions. Most recipes prepared with QPM had a higher protein quality than those prepared with CM.

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OBJECTIVE: Ten typical recipes from southwestern Colombia were evaluated at CIAT in Palmira, Colombia between 2008 and 2009. MATERIAL AND METHODS: The recipes were prepared in a traditional manner, using quality protein maize (QPM, with more tryptophan and lysine) or common maize (CM); each of these was either fresh kernel or dry grain, or white or yellow maize, per the recipe. The two types of maize were compared for their protein quality. RESULTS: Tryptophan concentrations were 0.011-0.072% and 0.012-0.107% for CM and QPM, respectively. Tryptophan values for QPM recipes were greater than or equal to those for CM recipes. Soluble protein ranged from 2.359-14.783 g/kg for CM and 3.339-16.839 g/kg for QPM. Except for one recipe, soluble protein in QPM recipes was greater or equal to that of CM recipes. In vitro protein digestibility was 75-84% for recipes prepared with both maize types. Only four recipes had a statistically significant difference between QPM and CM with regard to digestibility. CONCLUSIONS: Most recipes prepared with QPM had a higher protein quality than those prepared with CM.

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