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

210 I. Caldeira et al. / Journal of Food Engineering 76 (2006) 202–211
level had only effect on the contents of this compound
for CNF and CFL woods.
For the majority of the acids the toasting process
does not affect their contents, except for hexanoic and
propanoic acids. For the former it was found a decrease
with the increase in the toasting level and also it was detected
effect of interaction factors; so the toasting process
only affected the hexanoic levels of five types of
wood (CNF, CNG, CAST, CFA and CAM). Toasting
effect and interaction effect was also detected for propanoic
acid. For CNF, CAST and CFA the toasting level
did not affect the propanoic acid contents, although in
the other types of wood studied, higher toasting level increased
the quantity of this compound.
It can be also noted that the toasting level effect on
the amounts of cis-b-methyl-c-octalactone + 4-methylguaiacol
was significant, but for the trans-b-methyl-coctalactone
the toasting do not affect itÕs contents, which
disagree with the results obtained using French oak
wood by Chatonnet et al. (1989).
The principal component analysis (Fig. 5) shows that
the initial wood group division, made by the first component,
seems based on the toasting level, which increases
across the component. In fact the unheated
woods are located in the negative branch of this component,
in opposite to the strongly toasted woods, which
are located in positive branch of this component. Nevertheless
it seems that the division between the successive
toasting levels is not clear. This could be due to the
strong variability resulting from many uncontrolled
parameters during the heat treatment.
The variables, which influence most the first component,
are the furanic aldehydes (furfural, 5-methyl-furfural,
HMF), 4-hydroxy-2-butenoic acid lactone, vannilin,
propanoic acid and volatile phenols with a syringyl-type
structure, namely syringol and 4-allyl-syringol. The increase
in toasting level enhances the quantity of these
compounds in wood. These results could explain the
sensory significant differences found in the brandies
aged, in these barrels (Caldeira, Belchior, Clímaco, &
Bruno de Sousa, 2002).
4. Conclusions
This present work permitted the identification, for the
first time, of the 4-hydroxy-2-butenoic acid lactone in
oak and chestnut wood, moreover, also for the first
time, 2 + 3-methyl-1-butanol, benzaldehyde, acetovanillone,
b-methyl-c-octalactone, guaiacol, 4-methylguaiacol,
4-propylguaiacol, 4-ethylguaiacol, eugenol,
isoeugenol, 4-methylsyringol and 4-allyl-syringol were
identified in chestnut wood.
These results pointed out that the unheated wood discrimination
is possible based on certain volatile compounds
namely eugenol, cis-b-methyl-c-octalactone,
furfural, 4-hydroxy-2-butenolactone, hexanoic acid
and guaiacol. Nevertheless after the toasting process,
wood discrimination is weaker and it is only possible
to discriminate the American oak wood from the other
types of wood based on amounts of eugenol and cis-bmethyl-c-octalactone
present.
For the seven woods studied, including the Portuguese
chestnut, this work showed that the increase in
the level of toasting is related to the increase in the levels
of many compounds. The most affected were furanic
aldehydes (furfural, 5-methylfurfural, HMF), volatile
phenols (syringol and 4-allyl-syringol), propanoic acid,
4-hydroxy-2-butenolactone and vanillin.
Acknowledgements
The authors thank Madalena Miguel for technical
assistance, Sun Baoshan and Marlene Vaz for manuscript
revision and PAMAF-IED-2052 for the financial
support.
References
Abbott, N., Puech, J.-L., Bayonove, C., & Baumes, R. (1995).
Determination of the aroma threshold of cis and trans racemic
forms of b-methyl-c-octalactone by gas chromatography-sniffing
analysis. American Journal of Enology and Viticulture, 46(3),
292–294.
Alford, E. D., & Leffingwell. J. C. (1998). GC/MS of liquid ‘‘hardwood
smoke’’ extract. Available from http://www.leffingwell.com/
smoke1.htm.
Artajona, J. (1991). Caracterisation del roble según su origen y grado
de tostado, mediante la utilizacion de GC y HPLC. Viticultura/
Enologia Profesionalm, 14(5/6), 61–72.
Belchior, A. P., Caldeira, I., Tralhão, G., Costa, S., Lopes, C., &
Carvalho, E. (1998). Incidência da origem e queima da madeira de
carvalho (Q. pyrenaica, Q. robur, Q. sessiflora, Q. alba/Q. stellata
+ Q. lyrata/Q. bicolor) e de castanho (C. sativa) em características
fisico-químicas e organolépticas de aguardentes Lourinhã em
envelhecimento. Ciência e Técnica Vitivinícola, 13(1–2), 107–118.
Boidron, J. N., Chatonnet, P., & Pons, M. (1988). Influence du bois sur
certaines substances odorantes des vins. Connaissance de la Vigne et
du Vin, 22(4), 275–294.
Borralho, A. C. R. (1994). Estudo de substâncias provenientes da
madeira no envelhecimento de vinhos tintos. Suas incidências na
qualidade. (pp. 27–35). Relatório final do curso de Engenharia
Agro-Industrial, Universidade Técnica de Lisboa, Lisboa.
Brenna, E., Fuganti, C., & Serra, S. (2003). Enantioselective perception
of chiral odorants. Tetrahedron: Asymmetry, 14, 1–42.
Caldeira, I. (2004). O aroma de aguardentes vínicas envelhecidas em
madeira. Importância da tecnologia de tanoaria. (pp. 65–94).
Dissertação para obtenção do grau de doutor em Engenharia
Agro-Industrial, Instituto Superior de Agronomia–Universidade
Técnica de Lisboa, Lisboa.
Caldeira, I., Belchior, A. P., Clímaco, M. C., & Bruno de Sousa, R.
(2002). Aroma profile of portuguese brandies aged in chestnut and
oak woods. Analytica Chimica Acta, 458, 55–62.
Caldeira, I., Canas, S., Costa, S., Lopes, C., Carvalho, E., & Belchior,
A. P. (1998). Influence de lÕorigine du bois et de la technologie de
fabrication des fûts sur la qualité des eaux-de-vie Lourinhã pendant