Investigating Fruitiness Perception in Red and White wines

This provides results and conclusions from the entire project, although we may refer to previous reports. We have had a very exciting accomplishment with the adaptation of a chemometric method that can calculate chemical interactions resulting in specific sensory perceptions. This method, fuzzy set qualitative comparative analysis (fsQCA), overcomes the issues with traditional correlation analysis that made determining aroma chemical interactions very difficult. To date we have investigated 87 different compound combinations and their impact to fruit aroma in Pinot noir wine. By applying fsQCA we have found 5 compound sets that result in red fruit aroma in Pinot noir wine and 2 compound sets that result in dark fruit aroma in Pinot noir wine. The necessary and sufficient conditions found in these sets are supported by other work, but our results are the first to show the multiple combinations of compounds that can result in specific fruity aromas. We have also investigated 57 compound combinations for fruitiness in white wine. Since we were less sure about the calibrations used for fsQCA we ended up creating unique set variables to determine the necessary and sufficient conditions for different fruity aromas in white wine. Overall we found 5 compound sets that cause tropical fruit aroma, 2 compounds sets that cause red apple aroma, 1 compound set for pineapple aroma, 2 compounds sets for pear aroma, 4 compound sets for peach aroma, 1 compound set for orange aroma and 1 compound set for lychee aroma. For the compounds we investigated we did not get any compounds sets for citrus aroma and green apple aroma. We also incorporated nonvolatile factors into the analysis. In red wine we are investigating the effect of phenolic composition on fruitiness perception and in white wine we changed the residual sugar and ethanol concentration to determine its impact on fruity perception in white wines. Phenolic content in red wine was found to alter fruitiness perception, but the change in ethanol and sugar in white wine did not have an impact to aromas perception. This work has shown huge strides in understanding compound interactions that cause specific aromas in wines. To the point that we will be able to start building predictive models in the future that have much better success than any previous ones. With these models it will be possible to determine the impacts of different viticulture and winemaking practices to these wines without having to go through lengthy sensory studies and make real time decisions during the season for the desired wine quality parameter.