10 Aromatic Spoilage of Wines by Raw Materials and Enological Products 599
10.4.1.2 Cyclohexyl Isothiocyanate
Anocibar Beloqui (1998) demonstrated that a wine with a solvent or rubbery aroma
came from a batch of barrels that had been filled with a new hose. The wine from the
first filled barrel only had a few more g/L of benzothiazole than the wine from the
other barrels and, in any case, the concentrations were lower than 15 g/L. These
values are below the perception threshold for this substance in a synthetic solution
(50 g/L) and well below the perception threshold in red wine (200 g/L) reported
by Lavigne (1996).
Analysis of a sample from the hose pipe indeed showed the presence of benzoth-
iazole and when the chromatogram of this sample was compared to that of the wine
sample contaminated with this piping,there was a peak common to both of them.
The mass spectra of the compounds found in the wine (Fig. 10.3) and of the sample
from the hose were also similar. In both cases, from the library of reference spectra
this compound has been identified as cyclohexyl isothiocyanate: C 6 H 11 –N=C=S
and is a contaminant produced in the manufacture of rubber materials (Cocheo
et al. 1983).
10.4.2 Flavors Caused by Pesticide Degradation
For many years it was assumed that the residues of sulphurous pesticides caused the
“reducing” defects in wines (Burkhardt 1978).
Cantarelli et al. (1964) have shown that yeasts can use ethylene bi-thiocarbamates
and produce sulphurous compounds such as H 2 SandCS 2. Marshall (1977) described
the degradation mechanism of dithiocarbamates to ethylenediamine and CS 2 or to
ethylenethiouramide that would be transformed into ethylenethiourea and into CS 2.
Scan 2760 (38.762 min): ANGUIMC.D (*)41555867
7283115141(^55) #7677: Cyclohexane, isothiocyanato- (*)
58
67
72
83
85 98
141
30 40 50 60 70 80 90 100 110 120 130 140 150
30 40 50 60 70 80 90 100 110 120 130 140 150
0
2000
4000
6000
8000
m/ z- ->
Abundance
0
2000
4000
6000
8000
m/ z- ->
Abundance
Fig. 10.3Mass spectra of a compound found in a contaminated wine extract (top) compared with
that from the spectra library NBS75K.l. This compound is a contaminant produced during the
manufacture of cork materials (Cocheo et al. 1983)