Cadmium Removal from Aqueous Systems Using Opuntia albicarpa L. Scheinvar as Biosorbent.

The aim of this research was to investigate the use of a natural adsorbent like nopal (Opuntia albicarpa L. Scheinvar) for removing cadmium from aqueous solutions with low concentrations of this metal. Two treatments were applied to the cladodes: a dehydration to get dehydrated nopal (DHN) and heating up to 90°C to obtain a thermally treated nopal (TN). After examining the effect of various pH values (2-7), the capacity of each biosorbent was examined in batch sorption tests at different dosages (0, 500, 1000, 1500, 2000, and 3000 mg L(-1)). The results indicated that adsorption of cadmium to biomass of DHN and TN was highly dependent on pH and biosorbent dosage. The best removal of cadmium (53.3%, corresponding to q e of 0.155 mg g(-1)) was obtained at pH 4.0 by using the TN sorbent. Infrared and Raman spectra confirmed that cadmium removal occurred via adsorption to -OH functional groups.

Propiedades fisicoquímicas y sensoriales de harinas para preparar atole de amaranto / Physicochemical and sensory properties of flours ready to prepare an amaranth "atole"

El atole es una bebida prehispánica mexicana tradicionalmente preparada con maíz; sin embargo cereales como el arroz y el amaranto también han sido usados empleados. El objetivo fue caracterizar las propiedades fisicoquímicas y sensoriales de una harina para preparar una bebida (atole) a base de amaranto a fin de determinar su aporte nutricional. El análisis bromatológico del atole de amaranto y de las marcas comerciales (a base de maíz y arroz) fue realizado siguiendo las técnicas de la AOAC. El análisis de minerales se llevó a cabo mediante espectrofotometría de absorción atómica. La determinación de la viscosidad se realizó en un reómetro en un intervalo de temperatura de 25 a 90ºC. El perfil descriptivo cuantitativo (QDA) del atole de amaranto fue determinado por un panel de 10 jueces entrenados. El atole de amaranto presentó un mayor contenido de proteína y grasa que los atoles de maíz y arroz. En general, sodio y potasio fueron los macrominerales más abundantes. Los atoles de maíz y arroz presentaron una viscosidad constante de 20 a 84ºC, a partir de 85ºC se observó un incremento importante de ésta; en el atole de amaranto se detectó este incremento a 75ºC. Los descriptores definidos por los jueces entrenados para los perfiles descriptivos cuantitativos de los atoles de amaranto fueron: almidón, almendra/cereza, caramelo macizo, vainilla, fresa, nuez y chocolate. El atole de amaranto, respecto a los atoles de maíz y arroz, presentó el mejor perfil nutricional, destacando su aporte proteico.

Atole is a Mexican prehispanic drink prepared traditionally with corn; however, cereals as wheat, rice and amaranth have also been used. The aim of this study was to determine the physicochemical and sensory properties of an amaranth flour to prepare a drink (atole) mentioned above, in order to determine its nutritive value. Proximate analysis of the amaranth, corn and rice drink flours was determined by means of official techniques of AOAC. Mineral content was carried out by atomic absorption spectrometry. Viscosity was measured in a reometer from 25 to 90ºC. The quantitative descriptive profile (QDA) of the amaranth drink was studied by a trained panel of 10 judges. Results showed that the amaranth drink flour presented the highest protein and fat content compared to corn and rice drink flours. Sodium and potassium were the most abundant minerals in all flours studied. Corn and rice drink flours showed a constant viscosity from 20 to 84ºC, to 85ºC an important increase in this parameter was observed. This increase was detected in the amaranth drink flour to 75ºC. Descriptors defined by trained judges for the QDA of the amaranth drink flours were: starch, almond/cherry, caramel, vanilla, strawberry, walnut and chocolate. The amaranth drink flour, compared to corn and rice drink flours, presented the best nutritional profile; it is important to emphasize its protein content.

Manganese accumulation in plants of the mining zone of Hidalgo, Mexico.

Soil, sediments, water and plant samples from the mining zone of Molango were collected and analyzed and Mn-tolerant and Mn-accumulator plants were identified. Soil and sediments presented moderately alkaline and reducing conditions, a normal electrical conductivity, a sandy texture and medium-to-high cation exchange capacities. These properties favored the presence of Mn(2+), which is the form most easily assimilated by plants, and the total Mn concentration (11,637-106,104 mg kg(-1) dried weight, DW) was at phytotoxic level. Water was also an important Mn source. Equisetum hyemale and Telypteris kunthii survived in the presence of such Mn concentrations using an exclusion strategy, while Cnidoscolus multilobus, Platanus mexicana, Solanum diversifolium, Asclepius curassavica L. and Pluchea sympitifolia employed an accumulation strategy. These plants could be useful to re-vegetate and stabilize Mn tailings in order to decrease the erosion effects.

[Physicochemical and sensory properties of flours ready to prepare an amaranth "atole"]. / Propiedades fisicoquímicas y sensoriales de harinas para preparar atole de amaranto.

Atole is a Mexican pre-hispanic drink prepared traditionally with corn; however, cereals as wheat, rice and amaranth have also been used. The aim of this study was to determine the physicochemical and sensory properties of an amaranth flour to prepare a drink (atole) mentioned above, in order to determine its nutritive value. Proximate analysis of the amaranth, corn and rice drink flours was determined by means of official techniques of AOAC. Mineral content was carried out by atomic absorption spectrometry. Viscosity was measured in a reometer from 25 to 90 degrees C. The quantitative descriptive profile (QDA) of the amaranth drink was studied by a trained panel of 10 judges. Results showed that the amaranth drink flour presented the highest protein and fat content compared to corn and rice drink flours. Sodium and potassium were the most abundant minerals in all flours studied. Corn and rice drink flours showed a constant viscosity from 20 to 84 degrees C, to 85 degrees C an important increase in this parameter was observed. This increase was detected in the amaranth drink flour to 75 degrees C. Descriptors defined by trained judges for the QDA of the amaranth drink flours were: starch, almond/cherry, caramel, vanilla, strawberry, walnut and chocolate. The amaranth drink flour, compared to corn and rice drink flours, presented the best nutritional profile; it is important to emphasize its protein content.