Obtenção, caracterização e utilização de puba como materia-prima na produção de etanol

AUTOR(ES)
DATA DE PUBLICAÇÃO

1993

RESUMO

"Puba" was produced through six alternative experiments, using three cassava varieties and two types of containers and experimental conditions. The resulting "puba" was submitted to proximate composition, particle distribution, damaged starch, water and alcohol soluble acidity, blue value, water absorption, water solubility, pasting properties analyses and microscopic examination. The results from these analyses were used to caracterise and compare the "puba" with those of local comercial cassava starch (normal and fermented) and grated cassava puree obtained from both peeled and unpeeled cassava roots. Besides, the samples were submitted to 27 gelatinization studies at 85°C, 22 liquification trials with alfa-amilase and 39 saccharification tests with amiloglucosidase. The kinetics of total reducing sugar (TRS) production was traced by Somogyi-Nelson and 3,5 dinitrossalicilic acid (DNSA), thus establishing mathematical models relating graphically the variation of TRS with reaction time. The products of starch gelatinization and hydrolysis were used as raw materials for 22 alcoholic fermentations, whose results were compared to each other and to those obtained from the fermentation of a sucrose sample. Saccharamyces cerevisiae yeast M304-2C, a TRS concentration ranging from 29,90 to 120,24 g/l, at 36°C and a inicial ph of 4,0 were used in the twenty three fermentations conducted. The course of fermentation was accompanied through determination of celular mass concentration, pH variation, TRS consumption and alcohol production. The results were analysed with the help of the computer program (AEG), thus developing both the mathematical models and appropriate graphical representations. On the basis of time and cellular mass concentration results, a "Mendensian" - logistic model was established, and represented as [X] = [a/(1 + be-cT)] + d. The fermentation results, on the other hand, were used to calculate: the generation time; yield and productivity of cellular mass/substrate, ethanol/substrate, ethanol/cellular mass; percentage variation of cellular mass; specific growth rate; substrate consumption and ethanol formation; percentage utilization of substrate; global, theoretical and real efficiency and global, theoretical yield related to the consumed TRS. All these values were compared with internal control and it was verified that "Puba" lends itself as a viable raw material (of sthand) production from cassava. A fluxogram for its utilization in ethanol production was proposed.

ASSUNTO(S)

materiais granulados alcool - industria mandioca - industria

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