Production of aguardente of sugar cane of açucar for immobilized cells. / Produção de aguardente de cana de açucar por celulas imobilizadas.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Besides the economical and social importance of Brasilian sugar cane spirit, there aren t many studies about its production methods. The increasing demand of this product by internal and external markets leads to an increased attention to its quality. The Brasilian sugar cane spirit is very appreciated by its characteristic aroma and flavor, as a consequence of the fermentation process, as well as distilation and maturation been carried out in wood recipients. The main factors that influence the quality of spirit are the yeast strain and fermentation conditions. The yeasts utilized in fermentation come from the raw sugar cane, and go into the sugar cane broth during the extraction processoThey are characterized by a great quantity of differnt yeasts strains, although there are some dominating species which can vary during the year. The main problems facing the small distilleries are the lack of standardization and still law abiding. The copper, the volatile acidity and orgnoleptic exam are the major factors that usually skip the regulatory standards. The goal of this work were to select a yeast strain from a small distillery, to immobilize it in an specific support and to develop a reactor to promote a continuous fermentation, with the aim of increasing the productivity and reducing the undesirabile volatile by products that influence negatively the quality of the spirity. To do this, it was necessary to design and construct two stirred reactors linked in series, operated continuously. The mixing in the reactor was obtained with a magnetic stirrer and a centrifuge pump to recycle the broth into the reactors. The substrate utilized was only sugar cane broth and the yeasts were immobilized in calcium alginate. The experiment was initially conducted in batch culture. After the end of metabolic activity the contininuous feed was started until the sistem reach the steady state. The diluition rate was changed during the fermentation time and samples were analysed from ethanol, volatile by-products and sugars. As comparison, the amounts of volatile compounds and productivity were measured in the continuous fermentation with immobilized cells and in a conventional process with free cells. The continuous fermentation with immobilized cells led to a productivity of 4,42 giL/h, yield of 87,10 % and conversion of 98,72 %. The spirit obtained in this process presented acetaldehyde, 1-propanol and volatile acidity contents - compounds that contribute to a negative sensorial quality of spirity - lower than the ones obtained in the conventional process using the same yeast .

ASSUNTO(S)

aguardente fermentação productivity fermentation celulas imobilizadas aguardente produtividade immobilized cells

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