Producción de etanol a partir del mucílago de cacao (theobroma cacao) mediante fermentación alcohólica.

Abstract

The objective of the present investigation was to obtain ethanol from the cocoa mucilage (Theobroma cacao) above by means of alcoholic fermentation, in order to take advantage of and give an added value to this byproduct, which is discarded due to the lack of knowledge of many producers. cacaoteros of Ecuador. The characterization of cocoa mucilage was determined by physical-chemical analysis such as: pH by potentiometry, Total Acidity by Volumetry, Total Solids and Ash by Thermogravimetric method, Brix by Refractometry, Reductive Sugars by means of the 3,5-dinitrosalicylic acid method , fermentable sugars by high performance liquid chromatography (HPLC) and an elemental analysis using an elemental analyzer (Nitrogen, Carbon, Hydrogen, Sulfur) to know its composition with accuracy. The cocoa mucilage was obtained under aseptic conditions by squeezing fresh cocoa beans into Mayas. After filtration, the mucilage was sterilized at 121 ° C for 15 minutes in order to eliminate any microbial load. The fermentation process was carried out in an amber glass bottle sealed by a natural cork stopper in which the mucilage was added, for a few minutes nitrogen gas was bubbled and finally the yeast inoculum was placed. This process was carried out for 7 days at different stable temperatures of 25 ° C performed in an incubator, 30 ° C in a stove and 28 ° C in the environment, using the freeze-dried commercial yeast Saccharomyces cerevisiae. A control was carried out every 12 hours determining pH, reducing sugars by means of spectrophotometry and the content of ethanol by means of gas chromatography (Column and a flame ionization detector (FID)). The results of the characterization showed that the cocoa mucilage variety above has: 3.76 of pH, 14.95% of Total Solids, 18.11 Brix, 0.27% of Ashes, 1.77% of Acidity, 20.85 % of Reducing Sugars, in the elemental analysis we obtained 0.83% of Nitrogen, 45.92% Carbon, 5.39% of Hydrogen and <0.05% of Sulfur, of fermentable sugars contains: Glucose 62.52 ( gL), Fructose a 63.47 ± 0.05 (gL), Sucrose 45.89 ± 0.05 (gL), Cellobiose 1.52 ± 0.05 (gL). In the production of ethanol, 3 treatments were developed which during the fermentation process reached the following results: Treatment 1 (25 ° C), a pH of 3.91, reducing sugars, 7.089% and 7.39% ethanol; Treatment 2 (28 ° C), a pH of 3.96, reducing sugars 10.216% and 6.48% ethanol; Treatment 3 (30 °) a pH 3.97, of reducing sugars 2.423% and 11.62% ethanol. In conclusion, the cocoa mucilage of the Fino de Aroma variety (Above) represents an ideal substrate for the production of ethanol, and it was also established that treatment 3 is the most effective since it consumed almost entirely the sugars of the cocoa mucilage. , that is to say, it obtained a greater amount of ethanol and in less time, assuming that the production of ethanol besides being linked to the nutritional requirements (mainly nitrogen) of the yeast Saccharomyces cerevisiae is related to the temperature in which said process is subjected, being 30 ° C the optimum temperature of this alcoholic fermentation.