Characterization of key volatile compounds in red table wines produced from frontenac grapes (Vitis spp.)

Abstract

Frontenac (Vitis spp. MN 1047) is a new, cold-hardy red wine grape that is currently the most-planted grape cultivar in much of the Upper Midwest. Though typically described as having notes of cherry, black currant and spice, the volatile characteristics of Frontenac wine have not been investigated, and no structured evaluation of common sensory characteristics has been performed. To develop a standard set of aroma descriptors that characterize red Frontenac table wines, descriptive analysis was performed on six products. Thirteen sensory descriptors were developed and defined with reference standards; correlation plots indicated that attributes were discrete and not redundant. All 13 attribute descriptors were useful for describing and/or distinguishing between red Frontenac table wines. In order to determine odor active compounds, eight Frontenac table wines were evaluated using stirbar sorptive extraction (SBSE) combined with concurrent gas chromatography-olfactometry/ mass spectrometry (GCO/MS). Twenty-four volatiles perceived by panelists were identified via mass spectra comparison, and included five alcohols, fourteen esters, one lactone, two acids and two volatile phenols. Twenty-four of these were confirmed with LRI comparisons in separate GC/MS analyses using a C6 to C16 carbon ladder, and 23 were quantified in runs using a known concentration of internal standard. Analyses of wines produced from V. riparia clone #89, a parent of Frontenac, identified 16 volatiles common to Frontenac wines. Tentative identification, via GC/MS, of Frontenac juice with two days of skin contact suggested that four volatiles found in the wine may originate in the fruit.