Influência de alguns parâmetros na produção de cachaça: linhagem de levedura, temperatura de fermentação e corte do destilado

Abstract

In this work, the influence of different strains of yeast and temperature offermentation on the profile of the volatile fraction derived from the distillation of brewed sugarcane juice was evaluated. The existence of one or several chemical indicators to clearly define each distillate fraction, head, heart and tail, was also verified herein. These investigations contribute to the development of cachaça production, which is important, both economically and socially, for the country and mainly for the State of Minas Gerais. This thesis therefore aims to establish criteriafor quality control and good manufacturing practices to suit the product and its image in order to conquer the local and international markets. Therefore, we developed and built fermentation and distillation apparatus with technological innovations in semiindustrial scale so that such technology could be passed on to small farmers/producers. Fermentations were conducted using distinct strains of yeast(three Saccharomyces cerevisiae and one non cerevisiae) at temperatures of 18, 23 and 28ºC. The wines obtained were distilled and the collected fractions were analyzed using direct infusion electrospray ionization mass spectrometry (ESI-MS) and gas chromatography coupled with mass spectrometry (GC-MS). The results of principal component analysis (PCA) and hierarchical cluster analysis (HCA) appliedon the ESI-MS data revealed the grouping of the three distillate fractions (head, heart and tail). GC analysis revealed the importance of the selection of yeast strain as well as the control of the fermentation temperature; in most cases it was verified that lower temperatures favored a smaller production of secondary compounds andcontaminants. Furthermore, the use of closed vessels to promote fermentations under semi-anaerobic conditions allowed the decrease in the production of esters and higher alcohols, a factor that tend to improve the quality of the beverage. Results showed the prevalence of secondary compounds and contaminants in the head and tail fractions, which reinforces the need in the determination of the correct cuttingposition and disposal of these fractions. The distillation apparatus remarkably reduced the concentration of ethyl carbamate and precisely defined the separation between fractions (head, tail and heart). The distillator proved to be efficient and, being accessible to small producers, will allow the attainment of a more valuable beverage and thus may contribute to improve the socio-economic conditions for the establishment of labor in the rural area.