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STEROL SYNTHESIS IN RELATION TO GROWTH AND FERMENTATION BY BREWING YEASTS INOCULATED AT DIFFERENT CONCENTRATIONS
Author(s) -
Aries Vivienne,
Kirsop B. H.
Publication year - 1977
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1977.tb03798.x
Subject(s) - sterol , yeast , fermentation , brewing , oxygen , population , food science , chemistry , anaerobic exercise , biology , biochemistry , cholesterol , organic chemistry , physiology , demography , sociology
The sterol contents of brewing yeasts harvested from an anaerobic fermentation and inoculated into air‐saturated wort rise rapidly from ca . 1 mg/g dry yeast to ca . 10 mg/g and remain at this level until the oxygen is absorbed. After all oxygen is removed from the medium, sterol synthesis ceases and the concentration in the cells declines as growth occurs until a limiting value is reached, when reproductive growth ceases. In the presence of oxygen, sterols are present primarily as sterol esters; free sterols accumulate after oxygen uptake is complete. The total quantity of sterol which is synthesized in the presence of oxygen determines the extent of subsequent yeast growth. It is shown that the magnitude of sterol synthesis in the yeast population as a whole is influenced by the pitching rate.