Wine Discrimination and Analysis Using Quartz Microbalance Based Electronic Nose Technology

Wines are composed of numerous compounds that are complex, making them difficult to analyze. Wine evaluation and discrimination is typically done through chemical and human sensory evaluation. Unfortunately, both of these methods are time consuming and expensive. Therefore a new rapid analysis technique for wine discrimination and analysis is desired. The electronic nose has been suggested as an alternative to current wine discrimination techniques. In this study, a quartz microbalance-based electronic nose system was utilized to analyze the overall volatile components of wine. The electronic nose was optimized for Cabernet Sauvignon and Mouvédre wine to gain maximum sensor response from the sensors. Response surface methodology was used to determine the optimum sensor response by varying three experimental parameters: sensor temperature, sample temperature and equilibrium time. The maximum sensor response occurred at an equilibrium time of 20 min for each varietal and at a sample temperature of 55oC and 56oC for Cabernet Sauvignon and Mouvédre, respectively. The optimum sensor temperature selected for this study was 40oC for both varietals. Using the optimum sensor settings, the electronic nose was used to analyze Cabernet Sauvignon wines. Grapes were treated with ethanol spray (5%, and 10%) 13 weeks post-bloom, which has been shown to affect the overall quality of the final wine product. Wine samples were evaluated using chemical analyses, human sensory evaluation and electronic nose. Significant differences between the wines were observed based on pH, percent alcohol, and color intensity only. A consumer sensory panel consisting of 81 panelists was unable to differentiate amongst sample treatments. However, the electronic nose was able to differentiate between the control group and the treated samples 100% of the time. Canonical discriminant analysis of the data placed the 5% ethanol treatment as a sub-set of the 10% ethanol treatment. The results indicate that the electronic nose can be used as a discriminatory tool for assessing wines.