RESUMEN
Graphene-TiO2 composites have been investigated in various photocatalytic reactions showing successful synergy compared to pristine TiO2. In the present work, graphene oxide (GO) was synthesized by the Hummers method and then reduced graphene oxide-TiO2 composites (rGO/TiO2) were obtained by an in situ GO photoreduction route. X-ray diffraction, FTIR, Raman, UV-vis DRS, and photoluminescence were the main characterization techniques. The obtained composites containing 1 and 3 wt.% rGO were evaluated in the cyanide (50 mg/L) oxidation and Au-cyanide complex (300 mg/L) degradation under UV-A light. The composites showed higher photocatalytic activity than TiO2, mainly with the 1% rGO content. Cyanate and gold nanoparticles, deposited on the photocatalyst's surface, were the main byproducts during the photocatalyst assessment. The improved photocatalytic activity of the composites was attributed to a higher rate of electron transfer and a lower rate of charge recombination due to the chemical interaction of rGO with TiO2.
RESUMEN
The Phaseolus lunatus L. (lima bean) is a species of the Fabaceae family widely cultivated in the Northeast region of Brazil and is an important source of nutrients for the population. The lima bean has high genetic variability, which results in many cultivated varieties. However, there is little information about the cyanide levels, nutritional quality and sensory acceptance of these varieties, as well as about the changes caused by the cooking process, especially with regard to free cyanide contents. Therefore, the objective of this work was to evaluate the cyanide contents, nutritional quality and sensory attributes of lima bean varieties. Potential and free cyanide levels, quality attributes and a Qualitative Descriptive Analysis (QDA) were evaluated in raw and cooked grains. The study was carried out in a completely randomized design, with five lima bean varieties (Orelha de Vó, Branca, Roxinha, Rosinha, and Cearense), in 4 replications. Relatively to the raw ones, cooked grains presented larger size and smaller contents of ash, proteins, carbohydrates, potential cyanide and free cyanide, in the studied varieties. The Orelha de Vó lima bean showed higher mass of raw and higher firmness of cooked grains, which was judged to have the bitterest flavor among the others but showed safe levels of free cyanide after cooking. When cooked, Branca lima bean had a greater intention of purchase and global acceptance, due to its greater intensity of characteristic aroma and lower residual bitter taste.(AU)
A Phaseolus lunatus L. (fava) é uma espécie da família Fabaceae amplamente cultivada na região Nordeste do Brasil, sendo uma importante fonte de nutrientes e geração de renda para a população. A fava possui elevada variabilidade genética, o que resulta em muitas variedades cultivadas. No entanto, existem poucas informações sobre os níveis de cianeto, qualidade nutricional e aceitação sensorial dessas variedades, bem como sobre as alterações ocasionadas pelo processo de cocção, principalmente no que se refere aos teores de cianeto livre. Diante disso, o objetivo deste trabalho foi avaliar os teores de cianeto, qualidade nutricional e atributos sensoriais de grãos de variedades de fava. Os níveis de cianeto potencial e livre, atributos de qualidade nutricional e uma Análise Descritiva Qualitativa (ADQ) foram avaliados em grãos crus e cozidos. O estudo foi conduzido em delineamento inteiramente casualizado, com cinco variedades de fava (Orelha de Vó, Branca, Roxinha, Rosinha e Cearense), em 4 repetições. Relativamente aos crus, grãos cozidos apresentaram maior tamanho e menores teores de cinzas, proteínas, carboidratos, cianeto potencial e cianeto livre, das variedades estudadas. A fava Orelha de Vó apresentou maior massa nos grãos crus e maior firmeza nos cozidos, que foi julgada como sabor residual mais amargo entre as demais, mas apresentou níveis seguros de cianeto livre após cozimento. Quando cozida, a fava branca teve maior intenção de compra e aceitação global, devido a sua maior intensidade de aroma característico e menor sabor amargo residual.(AU)