Online estimation of assimilable nitrogen by electrical conductivity measurement during alcoholic fermentation in enological conditions.
The monitoring of alcoholic fermentation under enological conditions is currently poor due to the lack of sensors for online measurements. Such monitoring is currently limited to the measurement of CO(2) production or changes in density. In this study, we determined the potential value of measuring electrical conductivity. We showed that this measurement is related to the assimilation of nitrogen, which is typically the limiting nutrient, and directly correlated to ammoniacal nitrogen assimilation at any percentage of ammoniacal nitrogen in the medium. We also used electrical conductivity for the very precise monitoring of the kinetics of nitrogen assimilation after the addition of a pulse of diammonium hydrogen phosphate (DAP) during fermentation. The impact of initial conditions (e.g., must composition, grape variety, pH) remains unclear, but the robustness, precision and low price of the sensor used justify further studies of the potential value of measuring electrical conductivity on the pilot and industrial scales.
Colombié
Sophie
S
INRA, UMR Sciences pour L'oenologie, 2 place Viala, 34060 Montpellier cedex 1, France. scolombi@bordeaux.inra.fr
Latrille
Eric
E
Sablayrolles
Jean-Marie
JM
D000641:Ammonia / Q000378:metabolism; D004553:Electric Conductivity; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009584:Nitrogen / Q000032:analysis* / Q000378:metabolism; D009862:Online Systems; D010710:Phosphates / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism; D014920:Wine / Q000032:analysis*
D010710:Phosphates; C024788:ammonium phosphate; D000431:Ethanol; D000641:Ammonia; D009584:Nitrogen