Phenolic Characterization of Oregon Pinot Noir Wines PDF Download

Author: Ryan Elliott Hodgins
Publisher:
ISBN:
Category :
Languages : en
Pages : 242

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Author: Diane Youngeun Choo
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ISBN:
Category :
Languages : en
Pages : 180

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Author: Naomi Goldberg
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ISBN:
Category : Enzymes
Languages : en
Pages : 200

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Pinot noir has a reputation for lower color stability than other red wine varieties. Because it has relatively low anthocyanin and phenolic content and lacks acylated anthocyanin pigments compared to other red vinifera varieties, color extraction and stability are particularly important. Varying the processing during fermentation of red wine can produce high quality wines. Pectolytic enzymes are used in wine processing for many purposes from increasing juice yield and filtering rates to improving color and phenolic extraction. Macerating enzymes used in this study, Scottzyme Color Pro (Scott Laboratories), Scottzyme Color X (Scott Laboratories), Lallzyme EX (Lallemand), GB Rapidase EX Color (Gist Brocades), and Vinozyme G (Cellulo) were added to 1997 Oregon Pinot noir must prior to fermentation to observe color, aroma and flavor changes. These commercial enzymes have been reported to increase color and improve aroma and flavor of red wines. The effect of these enzymes had not previously been investigated on Oregon Pinot noir but the manufacturers reported increased polymeric phenols, polymeric anthocyanins, tannins, color stability, red hue and saturation of red wine varieties. These enzymes have varying manufacturer recommended usage levels and it is not known how the dosage levels and the enzymes themselves affect Oregon Pinot noir. Sensory evaluations of these wines, at a high and low dosage level, were conducted through free-choice profiling by winemakers and descriptive analysis from a trained panel. In addition, chemical analyses were performed and related to sensory panel results. Overall the addition of these enzymes to Oregon Pinot noir produced wines with greater purple, red descriptors and higher color intensity than the control wine from trained descriptive panel and winemaker panel results. In aroma, the enzyme treated wines were higher in vegetative and earthy descriptors compared to the control. GB Rapidase EX Color (Gist Brocades) was higher in bitterness flavor compared with other samples. Low enzyme wine treatments separated wine samples more from the control then high enzyme wine treatments. The color and appearance, aroma and flavor axes of the profile maps were not significant in the high enzyme treated wines as determined from the winemaker panel. Furthermore, the winemaker panel found acidity the only aroma or flavor descriptor significant in the high dosage ANOVA results. Whereas six descriptors in the low enzyme ANOVA results were significant in separating aroma and flavor samples. Except for Lallzyme EX (Lallemand) treated wine, the hunter colorimeter results showed all low enzyme treated wines were significantly (p

Author: Thomas M. Fitzpatrick
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ISBN:
Category :
Languages : en
Pages : 732

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Author: Heather Byrne Hjorth
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ISBN:
Category : Viticulture
Languages : en
Pages : 344

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Two vintages of Vitis vinifera cv. Pinot noir wine from a viticulture trial evaluating nitrogen fertilization, tilling and irrigation underwent descriptive analysis using a modified version of free-choice profiling. Wines were made from three field blocks of the twelve factorial combinations of Irrigation (Dry or Irrigated), Tillage (Tilled or not Tilled) and Fertilization (None, Foliar nitrogen supplementation or soil applied nitrogen). Irrigation was associated with lower anthocyanins and total phenols as well as lower color intensity and purple hue in both vintages. Irrigation increased vegetative and spicy character in the 1999 vintage while non-irrigated treatments were characterized by fruit, cherry and berry characteristics. Tilling significantly increased fruity flavor and body in the 1999 vintage and was associated with increased vegetative character in the 2000 vintage. In the 2000 vintage, non-fertilized treatments were significantly higher in floral aroma than the soil or foliar fertilized treatments.

Author: Matthew St. Johns Reid
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ISBN:
Category :
Languages : en
Pages : 284

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Author: Sarah Cahn Bennett
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ISBN:
Category :
Languages : en
Pages : 240

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Author: Honglei Zou
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ISBN:
Category : Antioxidants
Languages : en
Pages : 340

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Author: Shelby Rae Byer
Publisher:
ISBN: 9781085777421
Category :
Languages : en
Pages :

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Vineyard site influences the chemical composition of grapes and the overall characteristics of finished wine. The intricacies of how vineyard site impacts grape and wine composition and quality are of continual interest, and many studies have been performed which aim to develop better understanding of this phenomenon. This thesis explores this concept in a unique way, by examining characteristics of vineyard sites and the qualities of the resulting musts and wines from 15 vineyard sites in California and Oregon. Each of these sites is planted with Pinot noir clone 667, and 10 of 15 sites are grafted on 101-14 Mgt rootstock. All grapes were harvested and transported to the UC Davis teaching and research winery, where they were processed and fermented under controlled experimental conditions. Vineyard sites were categorized by their soil type, growing degree days, and precipitation. Growing degree days and precipitation were calculated and observed for three vintages by using nearby California Irrigation Management Information System (CIMIS) weather stations. Additionally, cluster sizes and grape berry sizes were measured and recorded to better understand site impact on cluster and grape morphology. Vineyards located in the same American Viticulture Area (AVA) sometimes share the same soil series. Grape musts were initially characterized by chemical analysis prior to fermentation, and multivariate analysis of the initial juice chemistry was performed. In 2016, regional clustering was more apparent based on initial juice chemistry than in 2017. However, in both years, general trends of similarity exist among vineyards based on their geography. Fermentations were monitored for grapes harvested from each vineyard site in 2017 and reveal different fermentation kinetics. Temperature profiles were controlled a consistent protocol by using jacketed fermentors with heating and cooling capabilities. No correlation was determined between the amount of yeast assimilable nitrogen (YAN) and the maximum rate of fermentation. Additionally, no trend was observed between fermentation behavior and AVA. Each vineyard site appeared to ferment uniquely, with the Santa Rita Hills vineyard site fermenting at the fastest rate. All vineyard sites finished fermenting to dryness. Finished wines from the 2015 vintage were observed through aging to assess how phenolic compounds change and develop in bottle. Wines were aged in screw cap enclosed bottle and analyzed at three sample points: 3 months post-fermentation, 8 months post-fermentation, and 20 months post-fermentation. Samples were analyzed by high-performance liquid chromatography (HPLC) coupled with a diode array detector (DAD). While individual vineyards displayed different initial amounts of each phenolic compound assessed, many shared similar patterns throughout aging. When all compounds at all sample points for all vineyards are assessed together, regional grouping by AVA are evident. To understand extraction of phenolic compounds into the must and fermenting grape juice, samples were taken and analyzed by UV-Vis for the 2017 vintage. Samples were taken during cold soak, fermentation, and post-press and analyzed at wavelengths of 280nm and 520nm. Measurement at 280nm gives an approximation for total phenolic compounds and measurement at 520nm give an approximation for anthocyanin content, though other materials in fermenting must and wine also absorb at 520nm. In general, absorbance values at both wavelengths continued to increase during fermentation. For some vineyard sites, a decrease in these values was observed at the end of fermentation and post-pressing, indicating a potential plateau in extraction.

Author:
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Category : Grape juice
Languages : en
Pages : 490

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Terroir is determined by a combination of factors in the vineyard including the grape varietal, geology and soil, soil hydrology, physiography, and climate. Although most studies have examined regional differences in wine flavors and associated provenance of wine based on chemistry, few have examined the chemistry of the soil and the ability to trace that chemistry to grape juice and, finally, to the wine. This dissertation examines what soil physical and chemical differences specific to this region might influence grape juice chemistry and wine chemistry. Wine-grapes in the Willamette Valley, Oregon, are grown on three major soil parent materials: volcanic, marine sediments, and loess/volcanic. Winemakers have observed differences in the flavor of Pinot Noir wine made from grapes grown on these different parent materials. This dissertation examines differences in the soil properties and elemental chemistry of the soil parent materials at various vineyards to document their effect on wine chemistry as a step towards understanding differences in flavor. All aspects of the terroir are controlled by carefully selecting vineyards with similar exposure and elevation, the same grape varietal and wine making techniques, and only the soils vary. The hypothesis is that the chemistry of the grape juice and wine reflect the soil in which the grapes were grown and that the three parent materials have soils that can be distinguished by their physical and chemical characteristics. Soil pits were excavated in 20 vineyards, soil properties were described in the field, and soil samples were later analyzed in the laboratory particle size, organic matter, color, pH, cation exchange capacity (ammonium acetate method), clay mineralogy (x-ray diffraction), and elemental chemistry (ICP-MS/AES). X-ray fluorescence was used to examine the pisolites. ICP-MS/AES was used for elemental analysis of grape juice and wines produced from these vineyards. Principal component analysis was used to compare soil physical and chemical characteristics, grape juice and wine chemistry. The physical characteristics of soils from all the three parent materials indicate: they are old (>50,000 years) based on their high clay content, low cation exchange capacity, red colors, and high Fe and Al content. These features indicate enough time has passed to reduce organic matter and other cations at depth, leave behind insoluble Fe and Al, and develop pedogenic clays. In my study region, volcanic and marine sediment soils are more developed with slightly lower acidity than the loess/volcanic soils. A new finding for this region is the presence of pisolites (Fe/Mg concretions) in the volcanic and the loess/volcanic soils, but absent in the marine sediment soils. Winemakers hypothesized that pisolites were present only in loess soils and influenced wine flavor in some way. Volcanic soils have the highest P, S, Fe, Co, Mn, and V concentrations and the lowest As and Sr values. Marine sediment soils have higher Cl and Sr and lower P, Co, Mn, Ba, and V concentrations than volcanic soils. Loess soils have the highest values of K and Mg and are similar to volcanic soils with higher P and V values and similar to marine sediment soils with higher Sr values. The main elements found to be significant in determining one parent material from another are V and Mn (volcanic soils), Mg and K (loess soils), and Sr (marine sediment or loess soils). Sr is slightly higher in grape juice and wine from vines grown on marine sediment parent material compared to volcanic and loess parent material, whereas Mn is higher in the juice and wine from grapes grown in volcanic parent material. P, S, Fe, Co, V, Cl, Ba, Mg, and K did not maintain their relative concentration levels from soil to grape juice to wine. The principal component analysis shows that soil and wine chemistry differs between parent material, but is inconclusive for grape juice chemistry.