PT - JOURNAL ARTICLE AU - B. W. Zoecklein AU - L. S. Douglas AU - Y. W. Jasinski TI - Evaluation of the Phenol-Free Glycosyl-Glucose Determination AID - 10.5344/ajev.2000.51.4.420 DP - 2000 Jan 01 TA - American Journal of Enology and Viticulture PG - 420--423 VI - 51 IP - 4 4099 - http://www.ajevonline.org/content/51/4/420.short 4100 - http://www.ajevonline.org/content/51/4/420.full SO - Am J Enol Vitic.2000 Jan 01; 51 AB - Grape glycosides are, in part, an important source of varietal wine aroma and flavor. Aglycones may be aliphatic residues, monoterpenes, sesquiterpenes, norisoprenoids, or phenolic compounds. Studies were undertaken to evaluate and compare methods of isolating non-phenolic or phenol-free glycosides. Phenol-free glycoside fractions were obtained by three isolation methods: the addition of polyvinylpolypyrrolidone (PVPP), isolation at pH 10.0 using C18 solid phase extraction cartridges, or isolation at pH 13.0 using OasisTM hydrophilic-lipophilic balance (HLB) extraction cartridges. Glycoside separation using the Oasis cartridges reduced the phenol content of the phenol-free glycoside fractions in Chardonnay juice and wines by an average of 49.7% compared to 33.6 % using C18. The differences in the phenol concentration in the phenol-free glycoside fractions with these two methods were greater with red juices and wines. For the Cabernet Sauvignon juice and wines the phenol concentration was reduced by an average 103% and 73% using the Oasis and C18 cartridges, respectively.