Cabernet sauvignon carbonyl compounds

Bertrand, 1994 Allen, 1995) decanal and ( )-2-nonenal, on the other hand, are associated with sawdust or plank odour (Chatonnet and Dubourdieu, 1996 1998). The principal carbonyl compound formed in MLF is 2,3-butanedione (diacetyl), whose level can improve, or affect, the wine with its butter-like or fat note (Davis et al., 1985). Diacetyl and 3-hydroxy-2-butanone (acetoin, the reduced form of diacetyl) are produced by pyruvate metabolism of yeasts and lactic bacteria, and their levels may increase two or three fold with MLF depending on the lactic bacteria strain involved (Davis et al., 1985 Martineau and Henick-Kling, 1995 Radler, 1962 Fornachon and Lloyd, 1965 Rankine et al., 1969 Mascarenhas, 1984). For diacetyl in wine sensory thresholds ranging from 0.2mg/L (in Cbardonnay) to 0.9mg/L (Pinot noir), and 2.8 mg/L (Cabernet Sauvignon wine), are reported (Martineau et al., 1995). 

The average contents of the carbonyl compounds identified in a Chardonnay and a Cabernet Sauvignon wine before and after MLF performed by inoculation of two different Oenococcus oeni commercial strains, are reported in Table 1.5. 

Table 1.4 Carbonyl compounds identified as PFBOA-derivatives in the chromatogram Figure 1.18 relative to GC/MS analysis of a Cabernet Sauvignon wine. I.S., internal standard. (Reprinted from Vitis, 41, 2002, Flamini etal., Changes in carbonyl compounds in Chardonnay and Cabernet Sauvignon wines as a consequence of malolactic fermentation, p. 109. Reproduced by permission of VITIS, journal of grapevine research).

Table 1.5 Average contents of carbonyl compounds identified in Cbardonnay and Cabernet Sauvignon wines before and after MLF operated by two different Oenococcus oeni bacterial strains, n.f. = not found. Amounts expressed as internal standard o-chlorobenzaldehyde (I.S.). Quantified on basis of 1 of 2 synlanti oxime peaks. Amounts calculated as 1-heptanol (I.S.) in the GC/MS analysis performed without synthesis of the PFBOA-derivafives.

A list of carbonyl compounds identified in Chardonnay and Cabernet Sauvignon wines (before and after MLF) and grappa samples (spirit produced by distillation of fermented grape marc), are reported in Table 5.8 (Flamini et al., 2002a 2005a). 

TABLE 5.8. Mean Contents of Carbonyl Compounds Identified in Chardonnay and Cabernet Sauvignon Wines2 and Grappa Samples ... 

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