Evaluation of the processing of three corn hybrids in ethanol production

Abstract

With a growing demand for energy, Brazil seeks to diversify its sources of raw materials. In this context, corn becomes an important source of energy production, since it is mainly used in the production of fuel ethanol. With this, it is worth considering a possible influence of the type of hybrid used, due to the difference in grain productivity during the cultivation period, which may directly impact industrial/fermentative efficiency. Therefore, the present study evaluated the reflexes of the processing of three corn hybrids in the production of ethanol. The experimental design was completely randomized, with four replications for each treatment. The hybrids used were: Dekalb 636, Pioneer 3754 and Syngenta 8454. The grains were crushed and immersed in acidified water (pH≈5.5) in the proportion of 250 g.L-1, addition of α-amylase enzyme (LpHera® Novozymes), subjected to heating for 1 h (100°C). The pastes were cooled to room temperature (25±3°C), filtered through a 20-mashe sieve, adjusting the Brix to 16% and the pH to 4.5, resulting in the must. The musts were inoculated with the industrial yeast TR (Thermo-Resistant), with the addition of the glucoamylase enzyme (LpHera® Novozymes). Fermentations were maintained in B.O.D. at 33˚C, and the physiological development of the yeast was evaluated. At the end of the fermentation process (Brix≤1%), the samples were centrifuged, obtaining wine samples. For the pastes and musts obtained, the parameters of Brix, Total Reducing Sugars (TRS), pH, Total Acidity, Total Phenolic Compounds and Starch were evaluated. For the wines, the Brix content, Total Residual Reducing Sugars (TRRS), pH, Total Acidity, Starch, Glycerol and Alcoholic Content were evaluated. Through the obtained results, it was observed that for the hybrids Dekalb and Syngenta, the Brix content of the samples did not obtain significant difference. Among the treatments, it is worth highlighting the TRS index of the Syngenta hybrid, which values of around 14.6% were verified, twice as much organic acids and higher starch content in the paste. For the fermentation process, no significant differences were verified, considering the three corn hybrids. As for the results of alcohol content and glycerol, there was no significant difference between the hybrids. Thus, it is concluded that the fermentative process and ethanol production are not influenced by grains of processed maize hybrids. However, highlighting the hydrolysis process, significant differences were verified, regarding the availability of fermentable sugars and starch, indicating a significant effect of the corn hybrid used.