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Time course of diacetyl formation during vinification with S accharomyces cerevisiae and O enococcus oeni co‐cultivation
Author(s) -
Mink R.,
Sommer S.,
Kölling R.,
Schmarr H.G.,
ScharfenbergerSchmeer M.
Publication year - 2014
Publication title -
australian journal of grape and wine research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.65
H-Index - 77
eISSN - 1755-0238
pISSN - 1322-7130
DOI - 10.1111/ajgw.12076
Subject(s) - oenococcus oeni , malolactic fermentation , diacetyl , winemaking , wine , chemistry , food science , fermentation , biochemistry , biology , bacteria , lactic acid , genetics
Background and Aims Diacetyl accumulation in wine, which has undergone malolactic fermentation by O enococcus oeni , is often associated with aromatic off‐flavours. Characterisation of the diacetyl‐related metabolic pathway helps to explain bacterial diacetyl formation during winemaking. The present study describes the time‐dependent formation of diacetyl during the vinification process after simultaneous, induced malolactic fermentation by freeze‐dried O . oeni on the basis of gene‐expression analysis of the citrate‐ and pyruvate‐derived pathways. Methods and Results After simultaneously induced malolactic fermentation in P inot B lanc by O . oeni , the dynamics of diacetyl formation were compared with citrate consumption and gene‐expression of the diacetyl‐related metabolic pathways. Diacetyl concentration showed two maxima: the first increase was primarily influenced by the activity of S accharomyces cerevisiae ; however, the second increase was induced only by O . oeni and correlates with bacterial citrate degradation. Expression of the alsS gene showed two significant responses; however, only the second response was affected by the citrate‐associated genes maeP and citE . Additionally, alsD and butA 2 were found to be continuously underexpressed during the winemaking process. Conclusions Taken together, we suggest that diacetyl accumulation during the vinification process by O . oeni is affected by citrate fermentation. The diacetyl‐related alsS gene, however, is also overexpressed independently by other substrates, which may also increase the intracellular pyruvate level resulting in diacetyl formation. Significance of the Study Characterisation of the time‐dependent diacetyl accumulation and its degradation during the vinification process is essential for the development of strategies that focus on the suppression of the diacetyl concentration below the sensory threshold.