Monitoring the aroma production during wine–must fermentation with an electronic nose

Abstract

This work discusses the feasibility of using the electronic nose for the on-line and real-time monitoring of the production of a complex aroma profile during a bioconversion process. As a case study, the formation of the muscatel aroma during the wine-must fermentation was selected. During wine-must fermentation, aroma compounds responsible for the organoleptic character are produced in the ppm range, while simultaneously one of the main metabolic products, ethanol, is produced in much higher quantities (up to 10% wt). Because the sensors of the electronic nose array are cross-selective to different volatile compounds, it was investigated in detail how far the electronic nose was able to evaluate the aroma profile along the fermentation. This article discusses and evaluates subsequently the integration of a membrane separation process-organophilic pervaporation-for selectively enriching aroma compounds relative to ethanol, to improve sample discrimination.

On-line monitoring of food fermentation processes using electronic noses and electronic tongues: A review

“…Aroma production along grape must fermentation has been monitored during the process [15]. In this study, the muscatel aroma was chosen because the profile formed as a result of yeast metabolism is complex, being composed of many compounds.…”

“…Ethanol acts as a co-solvent in the aqueous wine-must matrix and so the activity coefficient of the hydrophobic aroma compounds in the aqueous-phase is lowered, resulting in a decreased partitioning into the sample headspace [15]. This can lead to erroneous results with the electronic nose.…”

Wood production, wood technology, and biotechnological impacts

“…Changes in growth conditions influence their metabolisms, resulting in altering VOC patterns (Wheatley et al 1997. For example during spirits production with carbohydrate-rich substrates such as potato or wheat, the yeast Saccharomyces cerevisiae produces ethanol as main product, but the individual substrate provides different and characteristic aroma, caused by the minor components of the yeast and also the substrate (Conner et al 1998, Pinheiro et al 2001, Kafkas et al 2006, Porto et al 2006.…”

Monitoring Effects of Ethanol Spray on Cabernet franc and Merlot Grapes and Wine Volatiles Using Electronic Nose Systems

“…Each sensor is comprised of a different conductive material such as polypyrrole, polythiophene, polyaniline, polyacetylene, and polyindole, with a range of properties to allow discrimination among different types of volatiles, although cross-selectivity can occur (Mallikarjunan 2005, Pinheiro et al 2002. Sensor responses are stored as smellprints and compared with the present readings during identification (Cyrano Sciences Inc., manufacturer guidelines, 2000).…”