Characterization of free flavor compounds in traminette grape and their relationship to vineyard training system and location

ABSTRACT:  Free volatile flavor compounds in Traminette grape were characterized and compared to those in benchmark white cultivars by gas chromatography-mass spectrometry with headspace solid phase microextraction. In addition, the effects of vineyard site location (hot compared with cool based on growing degree days) and various training systems on yield components, standard characteristics (Brix, pH, and TA), and flavor compounds in Traminette grape juice were also evaluated for 2 seasons. Twenty-two free volatiles were identified in Traminette juice. The most abundant volatile compounds included hexanal, trans -2-hexenal, linalool, nerol, and geraniol. These compounds were quantified and compared with those in Chardonnay, Gewürztraminer, and Riesling juice. The hexanal concentration was the highest in Chardonnay, and trans -2-hexenal concentration was the lowest in Riesling. Traminette contained the highest amount of monoterpenes, especially geraniol. Concentrations of free volatile compounds in Traminette varied between the hot site and the cool site. In fact, the concentrations of 6-carbon aldehydes were higher in Traminette grown in the cool site than those grown in the hot site, whereas monoterpenes were higher in the hot site than in the cool site. Among the 5 training systems, vines on the vertical shoot-positioned produced the highest amount of monoterpenes, specifically geraniol. Our study suggests that Traminette is a flavorful cultivar that contains free volatile flavor compounds similar to the parent Gewürztraminer, but at much higher concentrations. The accumulation of odor chemicals in Traminette was affected by vineyard location and training system. Finally, geraniol was the most characteristic odor in Traminette, and its presence can be used as a quality indicator for this cultivar.