Utilização de levedura isolada da beterraba para desenvolvimento de uma cerveja pilsen, visando a produção em micro-cervejaria

• Autor(a) principal: Aoki, Bárbara Galdioli Nóbrega
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório do Centro Universitário Braz Cubas
• Texto Completo: https://repositorio.cruzeirodosul.edu.br/handle/123456789/2563
• topic: Fermentação; Cerveja; Leveduras (Fungos); CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

Yeasts are applied in biotechnological processes for the preparation of many foods and beverages, including beer. Yeasts can be isolated from different sources of plants and they are tested for industrial application in order to develop a differentiated product. The aim of the present work was to develop a Pilsen beer using yeasts isolated from natural sources (beet) in order to produce a beer with physicochemical characteristics and parameters recommended by national legislation. The isolation of the yeasts occurred in dichloran agar and the spread and maintenance of the strains in a medium composed of yeast extract and malt, with subsequent macroscopic and microscopic analysis. The inoculum propagation was carried out in a medium consisting by hydrolysed malt. The evaluation of the cell growth was done with the counting in a Neubauer chamber, specific speed, doubling time, optical density and dry weight of the inoculum produced in a bioreactor, in a shaker and the inoculum produced during fermentation of the beer. The quantification of glucose consumed during the inoculum propagation was analyzed by HPLC. The physicochemical analyses were carried out in the beer by the measurement of the pH, color, bitterness, alcoholic extract, real extract, apparent and original extract. It was observed that the growth of yeasts extracted from sugar beet is relatively greater when the inoculum was produced in a bioreactor with the result of 1.25 x 108 cells / ml compared to 8.9 x 107 cells / mL in the inoculum produced in shake flasks, and the double of time in the cell concentration in the bioreactor inoculum was 1.5 h and 1.7 h in the shaker. The methods of quantifying cell were similar, being the 8th hour, the peak of the cell concentration. The consumption of sugars was 87.5% during the preparation of the inoculum in bioreactor and 82.5% during the preparation of the inoculum in the shaker. The glucose consumption by the yeasts was inversely proportional to cell growth. The analyzed beer showed results of physicochemical analyses in accordance with the guidelines established by national legislation, with pH values of 4.8, color 8.58 EBC, bitterness 14.5 IBU, alcohol content 4.2%, original extract 12.22%, apparent extract 7.6% and real extract 4.1%.