Production of activated carbon from mango seed coat using chemical activation

Aim: This study was carried out find the feasibility of utilizing raw mango seed coat under various process conditions to produce the best activated carbon by chemical activation and compared with commercial activated carbon. Methodology: Activated carbon was produced by chemical activation under various process conditions such as different activation temperatures, activating agents, impregnation volume percentages and activation times for pyrolysis in a programmable electrical furnace with reactor in the absence of air. Results: The results were compared using phosphoric acid having 50% impregnation volume to other activating agents, the activating temperature was 400oC, activation time 1 hr, iodine number, methylene blue number, % yield and B.E.T surface area being 831 mg g-1, 212 mg g-1, 41.09% and 1114 m2 g-1 respectively. Interpretation: Carbon samples prepared using mango seed coat treated by H3PO4, showed clear open porous structures along with a larger pore size compared to commercially available activated carbon.

Evaluation of the temperature effect on vegetable oils by chemical analysis and ultraviolet­visible spectroscopy / Avaliação do efeito da temperature em óleos vegetais por analyses químicas e espectroscopia ultravioleta visível

Several methodologies could be used to characterize vegetable oil besides estimating thermal modification provided by high temperatures. These techniques are used as a proper tool to determine compositional and functional analysis of food ingredients and finished products. In general, vegetable oils are extracted from seeds like the rapeseed (canola oil) soybean (soybean oil), among others. In the present study vegetable oils such as canola and soybean were heated at a temperature of 100°C from 1h up to 28 h and the degraded products were measured to assess the oil stability at temperature. The determination of acid number, peroxide value and iodine number by chemical analysis was carried out for the estimation of the oxidative heat stability of these oils. Ultraviolet­visible spectroscopy strategy was also used to better comprehend this phenomenon, since it greatly improve the performance of measurements, in order to step up sensitivity. The findings demonstrated that vegetable oils thermal deteriorated as seen in the batocromic displacement of the samples heated and increasing the specific absorption in 350 nm. These data were capable to highlight the differences observed in the degree of unsaturation of oils.

Inúmeras metodologias podem ser utilizadas para caracterizar óleos vegetais, além de estimar modificações térmicas ocasionadas por altas temperaturas. Estas técnicas são usadas como ferramentas específicas para determinar a composição e função de ingredientes em alimentos e em produtos finais processados. Em geral, óleos vegetais são extraídos de sementes como a colza ou soja, entre outros. No presente trabalho, óleos vegetais como canola e soja foram aquecidos a temperatura de 100 °C entre 1 e 28 horas e os produtos de degradação foram medidos para avaliar a estabilidade do óleo na temperatura. As determinações da acidez, índice de peróxido e índice de iodo por análises químicas foram realizadas para estimar a estabilidade e a oxidação térmica dos óleos. A espectroscopia ultravioleta visível foi uma estratégia também utilizada para melhor compreender este fenômeno, uma vez que esta técnica aumenta o desempenho nas quantificações e quando se objetiva o incremento na sensibilidade. Os resultados demonstraram a deterioração térmica dos óleos vegetais através do deslocamento batocrômico das amostras aquecidas e o aumento da absorção a 350 nm. Estes dados ressaltam as diferenças observadas no grau de insaturação dos óleos.