PT - JOURNAL ARTICLE AU - Girard, B. AU - Fukumoto, L. AU - Mazza, G. AU - Delaquis, P. AU - Ewert, B. TI - Volatile Terpene Constituents in Maturing Gewürztraminer Grapes from British Columbia AID - 10.5344/ajev.2002.53.2.99 DP - 2002 Jan 01 TA - American Journal of Enology and Viticulture PG - 99--109 VI - 53 IP - 2 4099 - http://www.ajevonline.org/content/53/2/99.short 4100 - http://www.ajevonline.org/content/53/2/99.full SO - Am J Enol Vitic.2002 Jan 01; 53 AB - Changes in several physicochemical parameters of grape composition including pH, titratable acidity, soluble solids, weight, color, and phenolic content were examined for Gewürztraminer during ripening. Free and potentially volatile terpenes obtained by distillation were also assessed spectrophotometrically using an acidified vanillin assay and by gas chromatography-mass spectrometry (GC-MS). The colorimetric values of potentially volatile terpenes were estimated to account for nearly 84% of the bound terpenes, and the values of the free volatile terpenes reflected primarily the content of unsaturated aldehydes rather than the free terpenes. A procedure using selected ions specific to terpenes was developed to accelerate the analysis time of GC-MS chromatograms. Based on selected ion chromatograms, higher correlations were found for the bound terpene concentrations in Gewürztraminer vis-à-vis total skin phenolics, skin anthocyanins, and the traditional maturity indices of soluble solids and titratable acidity as compared to free terpene content.Acknowledgments: The financial support of the Science Council of British Columbia is gratefully acknowledged. The authors also thank Tom Kopp for technical assistance.