Mathematical modeling of convective air drying of quinoa-supplemented feed for laboratory rats

Drying kinetics of quinoa-supplemented feed for laboratory rats during processing at 50, 60, 70, 80 and 90ºC was studied and modeled in this work. Desorption isotherm was obtained at 60ºC giving a monolayer moisture content of 0.04 g water/g d.m. The experimental drying curves showed that drying process took place only in the falling rate period. Several thin-layer drying equations available in the literature were evaluated based on determination coefficient (r²), sum squared errors (SSE) and Chi-square (&#967;2) statisticals. In comparison to the experimental moisture values, the values estimated with the Logarithmic model gave the best fit quality (r² >0.994, SSE < 0.00015 and &#967;2 < 0.00018), showing this equation could predict very accurately the drying time of rat feed under the operative conditions applied

Toxicidade e acúmulo de flúor em hortaliças nas adjacências de uma fábrica de alumínio

Com o objetivo de avaliar o potencial de acumulação de flúor e o percentual deste elemento removido pela lavagem, quatro espécies de hortaliças foram expostas em área poluída. Spondias dulcis foi utilizada como bioindicadora de reação e apresentou sintomas típicos em resposta ao poluente. Somente a salsa apresentou sintomas. Apesar de aparentemente sadias, as folhas das outras espécies utilizadas para estudos microscópicos, exceto da cebolinha, evidenciaram alterações na superfície, principalmente associados aos estômatos. Houve redução na espessura do limbo, mais acentuada no manjericão e na cebolinha, havendo formação de tecido de cicatrização na couve e condensação do conteúdo das células epidérmicas na salsa. As folhas subuladas e eretas da cebolinha favoreceram o menor acúmulo do poluente; já na salsa, as folhas laminares, recortadas e paralelas ao solo contribuíram para a maior retenção. A lavagem das folhas removeu 34,1 e 73,9% do flúor na cebolinha e na salsa, respectivamente, indicando que a maior parte do poluente encontrava-se internamente na cebolinha e externamente na salsa. O cultivo destas hortaliças em áreas poluídas por flúor é inadequado, pois os teores do poluente estão acima do recomendado para o consumo, mesmo após a lavagem das folhas.To assess fluoride accumulation potential and the percentage of fluoride removed by washing, four herb species were exposed to a polluted area. Spondias dulcis was used as a responsive bioindicator and showed typical fluoride response symptoms. Symptoms were observed only in parsley. Although apparently healthy, the leaves of the remaining herbs, except for chives, showed surface damage associated mainly with stomata when observed under the microscope. A reduction in leaf thickness was also observed, most prominently in basil and chives. Scar tissue was observed in kale, and a retraction of the protoplast of the epidermal cells was observed in parsley. The subulate, erect leaves of chives accumulated less fluoride; on the other hand, parsley leaves are laminar, lobed and parallel to the soil, which contributed to higher pollutant retention. Washing the leaves removed 34.1 and 73.9% of the fluoride on chives and parsley, respectively, indicating that for chives, most of the pollutant was found inside the leaves, while for parsley, the pollutant was located on the outside. Growing these herbs in fluoride-polluted areas is not recommended, since pollutant percentages are above levels recommended for consumption, even after washing the leaves