exact management of dissolved gases of wines by ... - Oiv2010.ge

GC analyses of higher alcohols and esters of wine showed that only some esters underwent
significant losses being able to go up to 40%, especially ethyl-octanoate, ethyl-hexanoate,
isoamyl-acetate and hexyl-acetate, which are the most hydrophobic molecules, which thus
have most affinity for the membrane passage according to Diban et etc., 2008.
Comparatively, deoxygenation of the wines by nitrogen sparging with porous diffuser
causes important losses for the same molecules because of their volatility.
Sensory analysis by triangular test
A white and a red wine with respective O 2 initial contents of 0.79 and 0.82 mg/L and CO 2
initial content of 620 and 260 mg/L were deoxygenized by sparger and with WineBrane ® by
strip and combo modes (T° wines = 23 ± 1°C). The final average O 2 contents were
respectively of 0.20 (white) and 0.14 mg/L (red) and for CO 2 of 669 ± 68 (white) and 255 ±
36 mg/L (red). 15 days after, a triangular test was carried out by 19 tasters in order to compare
the wine before and after the deoxygenation for each wine and each treatment. No significant
difference was revealed to the α risk of 5%, in spite of the ester losses quoted previously.
Only the wines deoxygenized by sparger (porous diffuser) were considered to be different
from the control wines to the α risk = 14.6% (white) and 6.5% (red).
CONCLUSIONS
The dissolved gas management by membrane contactor constitutes a real progress during
the phase for conditioning of wines. A full automatic WineBrane ® unit integrated in a bottling
line (like at the wine coop of Besigheim) or in a bag in box line enables the simultaneous
control and adjustment of the two most important dissolved gases in oenology: the oxygen
major factor of the wines oxidation and the carbonic gas major factor of the sensory quality of
wines. Currently no competitive technology is available which is able to meet these needs
accurately and simultaneously in line.
The first tests showed that the main analytical parameters (alcohol, acidities and colour) are
not affected by the treatment. Only losses in some esters were observed without impact on the
tasting of the wine.
Further studies starting this year will focus on gaseous exchange and on the behaviour of
polyphenols. For that, other operating conditions like temperature variation, different gas
concentrations, wine types, inert gas consumptions … will be verified.
ACKNOWLEDGEMENT
The authors thank Magaly Angénieux from INRA 999UE Pech-Rouge for the GC analysis
of volatile compounds and the INOXPA Company for the provision of the WineBrane pilot
unit.
BIBLIOGRAPHY
Berta P., Spertino M., Vallini E., 2000. Controllo dell’ossigeno durante l’imbottigliamento
di vini frizzanti e spumanti. Industrie delle Bevande, 2000, XXIX dicembre, 618-622.
Boulet J.C., Vidal J.C., 1999. Dissolution d’oxygène à la mise en bouteille. Compte rendu
d’expérimentation INRA UE PR Gruissan.
Castellari M., Simonato B., Torinielli G.B., Spinelli P., Ferrarini R, 2004. Effects of
different enological treatments on dissolved oxygen in wines. Ital. J. Food Sci., vol16,nº3,
387-396.