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LIPID METABOLISM AND THE REGULATION OF VOLATILE ESTER SYNTHESIS IN SACCHAROMYCES CEREVISIAE
Author(s) -
Thurston P. A.,
Quain D. E.,
Tubb R. S.
Publication year - 1982
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.2050-0416.1982.tb04078.x
Subject(s) - chemistry , fermentation , yeast , biochemistry , metabolism , lipid metabolism , linoleic acid , ethyl acetate , organic chemistry , ethyl ester , fatty acid
The specific rates at which ethyl acetate and iso‐amyl acetate are produced by yeast increase markedly at that point in fermentation where syntheses of lipids ( i.e . saturated fatty acids and squalene) stop. An increase in the acetyl‐CoA: CoASH ratio, or a reduced availability of substrates (fatty acyl‐CoAs) for acyl transferases, are possible reasons for such a stimulation of ester synthesis. Increased rates of ester production are not sustained but contribute significantly ( ca . 30% for ethyl acetate) to the total concentration of acetate esters in beer fermented from 1·040 all‐malt wort. Addition of linoleic acid (50 mg litre −1 ) suppresses the induction of ester synthesis and reduces overall formation of both ethyl and iso‐amyl acetates by ca . 80%. Possibly, linoleic acid exerts these effects either by directly inhibiting the activity of an ester‐synthesising enzyme, or by allowing alternative use of acetyl‐CoA for the synthesis of saturated fatty acids.