Análise comparativa entre tratamentos térmicos industriais e por irradiação micro-ondas em caldo de cana-de-açúcar destinado à produção de etanol

Abstract

The ethanol is evaluated as an alternative fuel in the decrease of environmental problems and energy in the world, showing a process that adopts mechanisms for cleaner production and still standing out front of the rising prices of fossil fuels. The new technologies directed to the sugar-alcohol sector have been standing out in recent years, because with this feature, the industries can reduce the energy cost and production time. It is possible to simplify the process of treatment and clarification of the broth of sugarcane from the microwave irradiation technology. Since this reduces the use of inputs, being efficient against existing contaminating microorganisms in the production stages ethanol; therefore, it improves the fermentation performance of the process. In this way, the objective of this study was to compare the influences of thermal treatment, by microwave irradiation in the broth of sugarcane, contrasting to conventional treatment used in industry to produce ethanol. It was used three operating conditions for the treatment of broth by a microwave irradiation. In the laboratory experiments, were realized comparisons of the physicochemical analysis of the broth ‘in natura’, with broths obtained by treatments with irradiation and industrial With regard to the broths, purified and treated industrial manner, were analyzed: turbidity, color, soluble solids (ºBrix), pH, microbiological analyses and analyses of sugars, in addition to the alcohol content. With respect to the count of micro-organisms, we used the method pourplate for bacteria. To evaluate the results we used the analysis of variance – ANOVA – followed by the test of Tukey, and/or the non-parametric test of Kruskall-Wallis followed by multiple comparison by orders, all with significance level 0.05. The method of microwave power 840 W and exposure time of 3 minutes was further indicated by significantly reducing the rates of color, turbidity, and ºBrix, pH not suffering any significant reduction, there was no contamination by aerobic bacteria and the alcohol content reached 7,680 °GL. Showing a heat treatment effective, able to eliminate microorganisms, inactivate enzymes that can cause deterioration of the juice, controlling negative factors to the fermentation for obtaining the ethanol.