Acid-resistant strains of Saccharomyces cerevisiae yeast in the production of acid ales
DOI: 10.17586/1606-4313-2018-17-1-41-47
UDC 663
Ponomareva O.I., Borisova E.V., Prokhorchik I.P.
Keywords: acid ales, lactic acid bacteria, yeast, physiological activity of yeast, acid resistance of yeast strains.
UDC 663
Acid-resistant strains of Saccharomyces cerevisiae yeast in the production of acid ales
For citation: Ponomareva O.I., Borisova E.V., Prokhorchik I.P. Acid-resistant strains of Saccharomyces cerevisiae yeast in the production of acid ales. Vestnik Mezhdunarodnoi akademii kholoda. 2018. No 1. p. 41-47
Abstract
In the technology of acid ale production a combination of lactobacilli cultures and Saccharomyces cerevisiaebeer yeast is used. The main criterion for selecting a yeast strain is the resistance to the effect of low pH values: its physiological activity, which is the ability to ferment wort actively, while actively multiplying under the conditions of high acidity and providing the desired flavor profile of beer. Another indicator showing the stability of the yeast strain against the acidic environment, to which acid ales should be attributed, is the number of yeast dead cells in the total number of cells. Therefore, an important task is to analyze the processes of vital activity for various yeast strains under the conditions of increased acidity of the wort, the solution of which will allow producing acid ales with predetermined quality characteristics and providing the desired flavor profile of beer. In the paper the methods to evaluate the physiological activity of beer yeast strains of the Saccharomyces cerevisiae species under the conditions of wort fermentation together with lactic acid bacteria are considered. The results of studies of the pH effect on a dense and liquid nutrient medium on the physiological activity of various Saccharomyces cerevisiae yeast strains are presented. It was found that in a dense medium all the strains under investigation are growing actively at pH above 2.6 and, therefore, can be used for the preparation of acidic ale under pH conditions of from 3.6 to 3.2. Also, with the increase in the acidity of beer wort the number of viable (young and mature) cells is usually reduces and the number of dead ones grows. With the increase in the acidity of the liquid nutrient medium in the pH range of 2.6-2.0 the final cell concentration decreases, which is typical for all yeast strains under investigation. After the cultivation of the yeast in the liquid nutrient medium the morphology in the acidic medium was compared with the one of the control population before cultivation at pH 5.2. The number of yeast cells was calculated by Goryaev chamber. Based on the results of the researchthe most promising strain for the production of acidic ale was identified.
Abstract
In the technology of acid ale production a combination of lactobacilli cultures and Saccharomyces cerevisiaebeer yeast is used. The main criterion for selecting a yeast strain is the resistance to the effect of low pH values: its physiological activity, which is the ability to ferment wort actively, while actively multiplying under the conditions of high acidity and providing the desired flavor profile of beer. Another indicator showing the stability of the yeast strain against the acidic environment, to which acid ales should be attributed, is the number of yeast dead cells in the total number of cells. Therefore, an important task is to analyze the processes of vital activity for various yeast strains under the conditions of increased acidity of the wort, the solution of which will allow producing acid ales with predetermined quality characteristics and providing the desired flavor profile of beer. In the paper the methods to evaluate the physiological activity of beer yeast strains of the Saccharomyces cerevisiae species under the conditions of wort fermentation together with lactic acid bacteria are considered. The results of studies of the pH effect on a dense and liquid nutrient medium on the physiological activity of various Saccharomyces cerevisiae yeast strains are presented. It was found that in a dense medium all the strains under investigation are growing actively at pH above 2.6 and, therefore, can be used for the preparation of acidic ale under pH conditions of from 3.6 to 3.2. Also, with the increase in the acidity of beer wort the number of viable (young and mature) cells is usually reduces and the number of dead ones grows. With the increase in the acidity of the liquid nutrient medium in the pH range of 2.6-2.0 the final cell concentration decreases, which is typical for all yeast strains under investigation. After the cultivation of the yeast in the liquid nutrient medium the morphology in the acidic medium was compared with the one of the control population before cultivation at pH 5.2. The number of yeast cells was calculated by Goryaev chamber. Based on the results of the researchthe most promising strain for the production of acidic ale was identified.
Keywords: acid ales, lactic acid bacteria, yeast, physiological activity of yeast, acid resistance of yeast strains.
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