Volatile composition of oak and chestnut woods used in brandy ...

4-allyl-syringol were also identified for the first
time.
Some authors reported the presence of other phenols,
namely phenol, o-cresol, p-cresol, m-cresol, 4-ethylphenol
and methyleugenol (Chatonnet et al., 1989; Nabeta
et al., 1986; Nishimura et al., 1983) but these compounds
were not found in our wood extracts.
3.2. Effect of wood origin
The cooperage industry needs to have criteria for the
control of raw material. Thus, we decided first to compare
the 14 unheated wood samples (7 woods · 2 replicates),
in order to evaluate the possibility of
discriminating the different types of wood based on the
levels of volatile compounds, and after that, we compare
all the wood samples in order to evaluate if the wood
discriminating pattern is influenced by the toasting
process.
I. Caldeira et al. / Journal of Food Engineering 76 (2006) 202–211 205
Table 1 includes the quantitative analysis of several
volatile compounds in the unheated woods and the
ANOVA results, whereas Table 2 presents the results
from the analysis of all the different types of wood
(unheated and heated woods).
The high standard deviation indicates the strong variability
of the contents of these compounds in the different
types of wood, which is in agreement with the results
of other authors (Canas et al., 2000; Chatonnet &
Dubourdieu, 1998; Masson et al., 1995; Mosedale &
Savill, 1996; Simon, Conde, Cadahia, & Garcia-Vallejo,
1996).
The ANOVA showed (Table 1) that wood origin had
a very highly significant effect on the quantity of cis-bmethyl-c-octalactone
and eugenol, a highly significant
effect in the levels of acetic acid, furfural, 4-hydroxy-2butenoic
acid lactone, hexanoic acid, trans-b-methyl-coctalactone
and vanillin, and a significant effect on the
levels of guaiacol.
Table 1
Contents of volatile compounds in aqueous alcoholic unheated wood extracts and wood origin effect (results expressed as lg per g of dry wood)
Wood origin effect CNE CNF CNG CAST CFA CFL CAM
Acetic acid ** x 12.22a 67.97d 50.65c 19.09ab 70.20d 13.67a 34.74bc
SD 5.16 0.58 9.61 11.19 6.87 0.54 5.29
Furfural ** x 1.94a 12.51b 4.64a 2.27a 13.63b 4.51a 9.78b
SD 0.67 3.27 0.06 0.81 3.32 1.47 0.28
5-Methyl-furfural n.s. x 0.00 0.28 0.00 0.25 0.77 0.28 0.63
SD 0.00 0.40 0.00 0.35 0.19 0.40 0.31
4-Hydroxy-2-butenoic acid lactone ** x 0.00a 1.27b 0.00a 0.27a 1.50b 0.00a 1.26b
SD 0.00 0.48 0.00 0.39 0.35 0.00 0.43
HMF n.s. x 1.67 2.40 2.70 0.91 0.98 0.26 0.84
SD 1.29 0.43 0.07 0.14 1.38 0.37 0.05
Propanoic acid n.s. x 0.00 0.82 0.36 0.21 0.89 0.00 0.36
SD 0.00 0.04 0.50 0.30 0.40 0.00 0.51
Hexanoic acid ** x 0.64a 8.35b 1.47a 1.16a 8.76b 1.06a 12.52b
SD 0.00 4.27 0.06 0.71 2.21 0.01 2.27
trans-b-Methyl-c-octalactone ** x 2.31bc 2.68bc 2.47bc 0.23a 1.93b 2.87c 2.73bc
SD 0.23 0.79 0.24 0.33 0.06 0.35 0.21
cis-b-Methyl-c-octalactone *** x 6.72a 7.15a 5.30a 0.34a 4.93a 7.18a 35.40b
SD 3.79 3.00 0.67 0.48 0.30 1.39 6.44
Octanoic acid n.s. x 0.75 3.24 2.15 1.41 5.64 1.04 3.92
SD 0.16 2.40 0.74 1.21 1.88 0.09 1.69
Decanoic acid n.s. x 1.60 0.51 2.40 1.42 1.55 1.51 0.87
SD 0.22 0.72 1.70 0.45 0.08 0.78 0.02
Dodecanoic acid n.s. x 2.03 1.56 3.82 0.88 1.01 3.86 1.92
SD 0.01 0.05 2.21 1.24 1.42 0.13 0.50
Guaiacol * x 0.42a 1.25b 0.32a 0.38a 1.19b 0.09a 1.48b
SD 0.25 0.45 0.45 0.26 0.35 0.13 0.02
Eugenol *** x 0.94a 2.69b 1.08a 0.71a 1.17a 1.01a 4.48c
SD 0.02 0.52 0.48 0.06 0.15 0.11 0.33
Syringol n.s. x 0.39 0.36 0.00 0.53 0.36 0.00 0.00
SD 0.56 0.51 0.00 0.21 0.51 0.00 0.00
4-Allyl-syringol n.s. x 1.07 0.45 1.40 1.53 0.33 0.66 2.00
SD 0.64 0.63 0.60 0.06 0.47 0.93 1.12
Vanillin ** x 4.78bc 4.78bc 5.50c 2.90ab 8.32d 1.21a 5.78c
SD 1.32 0.10 0.56 1.25 0.89 0.29 0.06
Acetovanillone n.s. x 1.89 0.00 0.00 1.28 0.44 0.00 0.91
SD 1.24 0.00 0.00 1.81 0.63 0.00 0.13
x, means of two values; SD, standard deviation; means followed by the same letter in a row are not significantly different at the 0.05*, 0.01** or
0.001*** level of significance; n.s. without significant difference.