Measurement of 3-Alkyl-2-Methoxypyrazine by Headspace Solid-Phase Microextraction in Spiked Model Wines

285 Premium wine quality can be achieved only through a favorable balance between fruit, fermentation, and processingderived aromas and flavors. The 3-alkyl-2-methoxypyrazines produce vegetative odors characteristic of green bell peppers and peas. The olfactory threshold at which these compounds are sensed is extraordinarily low: 1 to 10 ng/L in water. These compounds, 3-isobutyl-2-methoxypyrazine, 3-sec-butyl-2methoxypyrazine, 3-isopropyl-2-methoxypyrazine, and 3-ethyl2-methoxypyrazine, are shown in Figure 1 in decreasing order of natural abundance [2]. As reported by Allen et al. [3,4], methoxypyrazine concentrations in grapes are influenced by variety, fruit maturity, season, climate, and solar exposure of the fruit. These plant metabolites are found in grape varieties including Cabernet Sauvignon and Sauvignon blanc and may detract from quality and varietal character. Measurement of these compounds is, therefore, of significant interest to the winemaker.