Tropical Fruit Aroma in Wine

The overall goal of this project is to produce Chardonnay wines with increased tropical
fruit aroma perception. In a previous study developed by Dr. Elizabeth Tomasino research group,
we found that wines with higher concentrations of fermentation esters and volatile thiols imparted
more intense tropical fruit aroma nuances. Therefore, in this project specific winemaking processes
(skin contact, β-lyase addition, and two fermentation gradient temperature regimes) were
performed with the intent to either increase or decrease these aromas in the wine. The first two
processes (skin contact and β-lyase addition,) are known for increasing volatile thiol
concentrations in wine. The latter (fermentation temperature) is expected to increase thiol
concentrations and preserve fermentation esters.

The accomplishments for the project for the 6 months have been to design and perform the
winemaking experiment for objective 1, measure the basic wine quality parameters (pH, titratable
acidity, malic acid, acetic acid, and ethanol content), and collect wine samples for the analytical
chemistry analysis. We have also performed a preliminary sensory descriptive analysis panel in
December 2020 (Projective Mapping combined with Ultra-Flash Profiling), but the results have
not been analyzed. Despite the Covid-19 lockdowns we are on track with this project and we are
currently developing a method to measure fermentation esters in the wines. To keep on track with
the project timetable we are working with a colleague at the University of Adelaide to have thiols
analyzed, as the access to the OSU MS facilities is limited due to COVID.