Influence of Stems, Petioles and Leaves on the Phenolic Content of Concord and Aurora Blanc Juice and Wine

Stems, petioles and leaves have historically caused operational problems at the processing plant and may alter juice and wine quality. Concord and Aurora Blanc grape samples, taken from the mechanical harvesters, were analyzed for total weight of material other than grape (MOG) and percent MOG. Hand-picked samples, with and without added stems, leaves, and petioles, were compared for phenolic content. Chemical analysis included total and phenolic fractions. Stems, petioles and leaves (i.e. MOG) have a definite affect on the chemical constituents. The total phenolic, flavonoid, and tannin contents of wine and juice increased as MOG content in the harvested grapes increased.

[1]  M. Quinn,et al.  Isolation and Identification of Ellagitannins from White Oak Wood and an Estimation of Their Roles in Wine , 1985, American Journal of Enology and Viticulture.

[2]  Vernon L. Singleton,et al.  White Wine Phenolics: Varietal and Processing Differences as Shown by HPLC , 1983, American Journal of Enology and Viticulture.

[3]  W. Kliewer,et al.  Further Investigations into the Relationship Between Anthocyanins, Phenolics and Soluble Carbohydrates in Grape Berry Skins , 1983 .

[4]  V. L. Singleton,et al.  The Nonflavonoid Phenolic Fraction of Wine and Its Analysis , 1979 .

[5]  R. Siegfried,et al.  The Extraneous Matter in Mechanically Harvested Wine Grapes , 1976, American Journal of Enology and Viticulture.

[6]  A. Noble,et al.  Effect of Leaf Content and Mechanical Harvest on Wine "Quality" , 1975, American Journal of Enology and Viticulture.

[7]  C. V. Wyk,et al.  Composition and Sensory Qualities of Wines Prepared from White Grapes by Fermentation with and without Grape Solids , 1975, American Journal of Enology and Viticulture.

[8]  C. Peri,et al.  An Assay of Different Phenolic Fractions in Winesa , 1971, American Journal of Enology and Viticulture.

[9]  V. L. Singleton,et al.  An Estimate of the Nonflavonoid Phenols in Wines , 1969, American Journal of Enology and Viticulture.

[10]  V. L. Singleton,et al.  Colorimetry of Total Phenolics with Phosphomolybdic-Phosphotungstic Acid Reagents , 1965, American Journal of Enology and Viticulture.