14C-10 |
Use of dehydrated yeast (Saccharomyces ssp.) by spray dryer in the production of beer |
M. A. SALGADO-CERVANTES1, D. M. Hernandez-Moreno2, G. C. Rodríguez-Jimenes2, and M. A. García-Alvarado3. (1) UNIDA, Instituto Tecnólogico de Veracruz, Av. Miguel Angel de Quevedo 2779, P.O. Box 1420, Veracruz, 91860, Mexico, (2) Chemical and Biochemical Dept., Instituto Tecnológico de Veracruz, Miguel A. de Quevedo No.2779, Col. Formando Hogar, Veracruz, Ver., 91897, Mexico, (3) Chemical and Biochemical Dept., Instituto Tecnologico de Veracruz, Miguel A. de Quevedo No.2779, Col. Formando Hogar, Veracruz, Ver., 91897, Mexico JUSTIFICATION There are some researches about the effect of spray drying process variables over the improving of the dried brewer’s yeast viability. However, these works have not validated the use of this dehydrated yeast in the production of beer. OBJECTIVE The aim of this work was to validate the use of yeast (Saccharomyces ssp.) dehydrated by spray drying for the production of beer. METHODS Microbiologic tests were made in order to evaluate the level of contamination on the dehydrated yeast. The re-hydration variables were: medium (peptone in water and water), yeast type (freshly dehydrated and stored), temperature (9 and 25 °C), agitation time (15 and 30 min) and speed (200 and 300 rpm). During the re-hydration yeast viability was evaluated by growth in inverted plate. The beer was elaborate through the fermentation of a wort prepared with a commercial formula inoculated with dehydrated yeast and fresh yeast, evaluating sugars (method DNS), final production of alcohol (beer analyzer), pH, O2 dissolved, a-ANL and final color (Lovibond values) RESULTS It was found that the dehydrated yeast presented bacterial contamination. However at fermentation temperature (10°C), the growth of these ones was not observed. The parameters evaluated for the re-hydration have not significant effect over viability, so it is suggest using anyone of the proposed conditions. The fermented product obtained with both dehydrated yeast reached an alcohol level of 1.4 y 1.8% (v/v), while for yeast cream 5.5% of alcohol was obtained. Not significant difference was found for the evaluated parameters between dehydrated yeast, however significant difference was found between them and the reference (yeast cream) for residual sugars, alcohol production, pH, a-ANL and O2 dissolved. SIGNIFICANCE At the present conditions, the alcohol level obtained with dried yeast was below to the required, however the optimization of fermentation conditions could change this conclusion.
Session 14C, Food Microbiology: Food mycology
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