Download or read book Effects of Ethanol Tannin and Fructose on the Sensory and Chemical Properties of Washington State Merlot written by Anne Carolyn Secor and published by . This book was released on 2012 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Impact of Wine Components on the Chemical and Sensory Properties of Wines written by Remedios R. Villamor and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The wine matrix includes a variety of compounds that influence wine quality. The overall objective of this study was to examine the relationship between the matrix components and sensory attributes of wine. To address the issue on wine quality as related to tannin and polymeric pigments, the effect of initial tannin concentration, storage time and temperature on chemical and sensory properties of young bottled Cabernet Sauvignon and Merlot wines was studied. In general, storage treatment resulted in a significant increase in small polymeric pigment (SPP) with a decrease in anthocyanin (p [less than equal to] 0.05). Tannin concentration was directly related to large polymeric pigment (LPP) and correlated with perceived astringency (r = 0.882). Increased perceived bitterness was associated with storage at 32 & ordm;C for 70 days. In addition to tannin content in wine, further experiments investigated the interaction of tannin with ethanol and fructose concentrations on the headspace concentration of eight odorants in model wine. In general, increased tannin concentration exhibited a salting-out effect while fructose induced a salting-in effect, both of which were largely dependent upon ethanol concentration. The net magnitude effect was a reduction in the odorants' headspace concentration dominated by ethanol. Odor detection thresholds increased between 2 and 10,000-fold, lowering the odor unit values (OUV). The impact of ethanol, tannin and fructose concentrations on the sensory properties of model red wines was also evaluated. Principal component analysis (PCA) differentiated the model wines based on factor 1 (floral, fruity and caramel), factor 2 (earthy and herbaceous) and factor 3 (sulfur, spicy, woody, and bitterness). Analysis of variance (ANOVA) results showed a significant impact of ethanol concentration on these factors (p [less than equal to] 0.05). Tannin and fructose, and all interaction effects were not significant. These results highlighted the influence of major wine components and their interactions on sensory perception. Viticulturists and winemakers are suggested to consider the information obtained in this research when making decisions to optimize wine quality.

Download or read book Effects of 4 ethylphenol and 4 ethylguaiacol on the Sensory Properties of Washington State Cabernet Sauvignon and Syrah written by Sarah Michaux and published by . This book was released on 2011 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Influence of Wine Components on the Chemical and Sensory Quality of Wines written by Charles Diako and published by . This book was released on 2016 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wine is an alcoholic beverage containing numerous compounds that contribute to its overall quality. The overall objective of this dissertation was to examine the influence of matrix interactions in commercial red wines on the sensory and chemical properties of wines, and explore advanced methods of mathematical analyses of these data. In the first study, the influence of these matrix components and their interactions on wine quality was examined. Commercial Merlot wines (n=61) were evaluated for wine chemistry parameters, with the matrix components of interest identified as alcohol, tannin and mannoproteins. Sensory evaluation results showed complex interactions among tannins, alcohol and mannoproteins on the perception of most aromas, flavors, tastes and mouthfeel attributes (p0.05). Since human subjects vary in their sensory perceptions, panel reproducibility and precision was addressed. Panelists' variation in attribute evaluations was conceptualized as a linear operator called a bias matrix for feedback calibration and correction of panelists' evaluations. Results showed that the bias matrix corrected the panelist ratings of the samples, leading to higher reproducibility and precision. No significant differences (p0.05) were found between the original and corrected means. Predictive filtering showed that the panelists' corrected means for the attributes were closer to the predicted panel mean compared to their unfiltered means. The application of the electronic tongue for the assessment of wine quality was further explored. Strong correlations (r2>0.930) were reported between the electronic tongue and the sensory perceptions of sweet, sour, bitter, burning, astringent and metallic. Further research on the application of the electronic tongue to discriminate among wines and building predictive models was performed. Non-linear methods showed high discrimination among the commercial wines (90.1%), with high prediction accuracy of the electronic tongue output using the chemical parameters ([greater than/equal to sign] 90.0%). These results showed the dependence of the intensity of the electronic tongue signal on the chemical components of the wines. This dissertation demonstrated how wine matrix components influenced perception through suppression and enhancement of various sensory attributes. In addition, advanced methods of chemical and sensory data analysis were developed and validated. Results from this study will be useful for winemakers for wine quality optimization.

Download or read book Instrumental and Sensory Evaluation of Red Wine Astringency written by Scott Clifford Frost and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The presented work aimed to explore the chemical and sensory relationship of red wine astringency. Two sets of experimental Merlot wines were utilized. The first set of wines were produced at the Washington State University Irrigated Agriculture Research and Extension Center (WSU-IAREC), then sent to UC Davis for chemical and sensory analysis. This set of wines employed a factorial design to evaluate the relationship of tannin, acid, and ethanol concentration on astringent perception. The factorial design allowed for evaluation of the effect of each factor on the response variable. Descriptive analysis (DA) and temporal dominance of sensation (TDS) were used to describe the sensory response. A five-factor analysis of covariance (ANCOVA) was applied to the DA data. The results showed significant effect of tannin and acid concentration, but ethanol concentration was not a significant effect. The analysis of the TDS data was dictated by the ANCOVA results. TDS curves were constructed by factor level only for significant effects as shown by the ANCOVA. The use of a factorial design for the analysis of TDS data was novel. These results are contained in chapter 2. The second set of experimental wines were produced at The UC Davis Teaching and Research Winery. These wines focused on altering chemistry and sensory through winemaking. Nine cap management and extended maceration treatments were evaluated. Extended maceration was applied to c.v Merlot grapes for 1, 2, 4, 6, and 8 weeks. In addition, a punch down treatment and two submerged cap treatments were also evaluated. The treatment effects were characterized using descriptive analysis, polyphenol measures, basic wine parameters, and volatile analysis. Length of extended maceration defined the astringent texture of the resulting wines, while bitter taste and pepper spice aroma were defined by the type of cap management. The chemical and sensory results relating to winemaking are presented in chapter 3. The fourth chapter explores the relationship of descriptive analysis and temporal dominance of sensation. The DA and TDS results from the maceration experiment are utilized to compare and contrast the two sensory techniques. Similar results were shown between the DA and TDS results for “hot” taste, but maximum dominance rate for astringency and bitter were not correlated with maximum DA intensity. In addition, correspondence analysis was applied to the TDS frequency table in order to project the results into a multivariate space.

Download or read book The Impact of Fining on the Chemical and Sensory Properties of Washington State Chardonnay and Gew rztraminer Wines written by Melissa Sanborn and published by . This book was released on 2008 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Influence of Alcohol Content on the Consumer Acceptance of Red Wine and Threshold Values of Selected Wine Odorants written by Allison B. Beall and published by . This book was released on 2010 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Sensory and Chemical Properties of Wines as Influenced by the Presence of Different Wine Bacteria and Yeasts written by Victoria Dawn Paup and published by . This book was released on 2021 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wine quality is a complex concept that is greatly influenced by its sensory characteristics and chemical composition, and many factors can contribute or detract from quality. The overall objective of this dissertation was to examine microbiological factors and their influence on wine quality using sensory evaluation and analytical testing methods. In the first study, the ability of the electronic tongue and experienced sensory panelists to discriminate among wines inoculated with spoilage microorganisms over storage was evaluated. Merlot wine was inoculated with spoilage microorganisms, in particular Brettanomyces bruxellensis, Pediococcus parvulus, Acetobacter pasteurianus, and Lactobacillus brevis, and tested weekly. Results showed that the electronic tongue discriminated among the inoculated wine samples starting at Day 21 of storage, while the experienced sensory panelists were unable to discriminate until Day 28. Therefore, the electronic tongue was demonstrated to be a useful tool for early detection of wine faults. In the second study, the influence of storage on the sensory and chemical characteristics of wines made with pectinase-producing non-Saccharomyces yeasts (NSY). The addition of NSY in Merlot wine increased cherry flavor over storage (p 9́Þ 0.05), an attribute often associated with wine quality. Additionally, significant differences were observed in pH and glycerol concentration in the wine. Some NSY that produce pectinase have been shown to increase polysaccharide concentrations which can improve mouthfeel characteristics. Building on this, providing sufficient substrate (pectin) may increase the activity of this enzyme. Therefore, the final study evaluated the influence of pectinase producing NSY on the sensory and chemical characteristics of wined with varying amounts of pectin. In both red and white wine, significant differences (p 9́Þ 0.05) were observed in the chemical parameters, in particular pH and D-galacturonic acid; however minimal differences were found in the sensory characteristics. Overall, this research advanced the understanding of how wine quality is affected by different wine microorganisms. In particular, new sensory and analytical methods for more rapid wine fault detection were developed, and a deeper understanding of the potential utilization of pectinase producing NSY to elicit chemical and sensory change was found.

Download or read book Chemical and Sensory Assessment of Astringency in Washington State Red Wines written by Josie L. Landon and published by . This book was released on 2007 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interactions Between Ethanol Storage Temperature and Sulfur Dioxide that Affect Brettanomyces Bruxellensis in Merlot Wine written by Taylor Adam Oswald and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impact of the Wine Matrix on the Perception of Finish in Red Wine written by Allison Kathleen Baker and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wine finish, the flavors, tastes, and mouthfeels that linger after swallowing wine, contributes to wine quality. The objective of this study was to investigate red wine finish, including the influence of the wine matrix on sensory attributes. Results from time-intensity trained sensory evaluations of flavor finish as a function of tannin and ethanol content indicated that the duration of flavor finish was extended by higher ethanol content. This longer finish of the high ethanol treatments was more acceptable than the shorter finish of the low ethanol treatments. Increased tannin levels extended the duration of finish for bell pepper flavor but significantly decreased consumer acceptability across all flavors. These results provide wine makers with practical knowledge to consider when making decisions that impact the tannin or ethanol profiles of their wines. These studies also exposed the need to develop methodology to further investigate wine finish. To address these methodological needs, a recently introduced dynamic sensory methodology for trained panelists, Temporal Check-All-That-Apply (TCATA), was used for the characterization of wine finish in wines varying in ethanol content. Results indicated that the finish of the high ethanol treatments were described by astringency, heat/ethanol burn, bitterness, dark fruit, and spices, while the finish of the low ethanol treatment was characterized by sourness, red fruit, and green flavors (p≤0.05). Consumers (40%) liked the finish of the low ethanol wine compared to the high ethanol or commercial wines (both ∼ 60% consumers) (p≤0.05). Finally, methodology for instrumental analysis of wine finish using in-mouth Stir Bar Sorptive Extraction (SBSE)/gas chromatography was developed. Using this method, different concentrations of volatile compounds were detected in the mouth at varying times throughout the finish (p≤0.05). These results demonstrated the application of this method for quantification of volatiles as they contribute to wine finish. The application and development of new methodologies (TCATA and in-mouth SBSE/GC-FID) for red wine finish characterization has advanced the ability to characterize temporal qualities. Overall this research has contributed to the previously understudied area of wine finish, demonstrating the influence of the wine matrix on the wine finish as evaluated by trained panelists, consumers and instrumentally.

Download or read book Predicting Sensory Attributes Found in a Model Wine Using Singular Value Decomposition and Support Vector Machines written by Daniel Archer Dycus and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Influence of Titratable Acidity on the Perceived Astringency in Merlot Wine written by Kmytro Kuzyk and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Chemical and Sensorial Effects of Plant based Fining Agents on Washington State Riesling and Gew rztraminer Wines written by Laura Ellen Hill and published by . This book was released on 2009 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phenolic Management in Red Wines written by Luis Federico Casassa and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The extraction into wine of selected phenolics as affected by season, regulated deficit irrigation (RDI), fruit maturity, and selected maceration conditions was studied. Pomace recovery, color, and sensory aspects were also investigated. In addition to a control treatment (10 days of skin contact), the maceration techniques studied included extended maceration (EM, 30 days of skin contact) and bleed-off (i.e. saignee) applied to reduce must volume by 16%. The influence of fruit maturity and ethanol were studied by producing wines from fruit with different sugar levels, and by artificially manipulating sugar levels before fermentation to generate different ethanol levels during maceration. Preparative HPLC fractionation of wine proanthocyanidins (PA) followed by HPLC-DAD-MS analysis was undertaken to determine PA distribution. Sensory properties were studied using Quantitative Flavor Profiling and Descriptive Analysis. Wines made from ripe fruit (ca. 24.5 Brix) extracted 16% of the available tannins (of which 79% were seed-derived tannins) whereas in unripe fruit (ca. 20 Brix) this extraction was 12% (76% of seed-derived tannins). Ethanol differences as high as 2.7% v/v during maceration had no effect on tannin and anthocyanin extraction, or in the proportion of seed- and skin-derived tannins. Wines obtained from ripe fruit were characterized by attributes such as viscous mouthfeel, sweetness and fruit-derived aromas. Wines made from unripe fruit were characterized by attributes such as fresh vegetal, acidic and lower color saturation. Wine PA distribution followed a non-normal, Rayleigh-type distribution, with concentration peaks at mean degree of polymerization (mDP) 2 (22 to 27% of total PA mass) and at mDP 6-7 (12 to 17% of total PA mass). The overall effect of EM resulted in increased tannin extraction from seeds (73 to 80% of seed-derived tannins), lower anthocyanin content, and decreased wine color saturation. This effect was independent of the maturity level and the EtOH concentration. EM increased astringency by 25 to 34% relative to control wines, and either did not enhance aroma, or was found to decrease fruity aromas. Saignee increased the anthocyanin and tannin content during maceration, promoting the formation of polymeric pigments while favoring a comparable proportion of skin- and seed-derived tannins.

Download or read book Sensory and Chemical Effects of Cross Flow Filtration and Pumping on White and Red Wines written by Peter Andrew Buffon and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the world of modern vinification, cross flow filtration and pumping are widely used. In the absence of systematic studies examining the effects of these unit operations on the resulting wine, winemakers are sometimes reluctant to use them to process their wines. Because cross flow filtration can not be accomplished without pumping, both of these unit operations were studied . Cross flow filtration is an increasingly common post-fermentation process in the wine industry. Because of the nature of the membranes used in this process, our hypothesis was that cross flow filtration would not have a significant impact on the sensory or chemical properties of either white or red wines. To investigate this, a California white wine blend and a California red wine blend were filtered in three 570 L lots using a Bucher Vaslin cross flow unit with a nominal 0.22 micron polyethersulfone membrane. The unfiltered control was sent directly to the bottling line without filtration. Panelists evaluated the wines nine times during an eight-month descriptive analysis panel with replicated tasting at each time point. UV-VIS spectrophotometry and the Adams-Harbertson assay were used to determine color and phenolic content of the filtered and unfiltered wines respectively. The effect of filtration was found to be significant for one sensory attribute out of 16 total measured in the white wine. Similar analysis for the red wines indicated that six sensory attributes were significantly different out of 16 total in the red wine. Unfiltered red wines were found to be higher in earthy, grassy, oak, and smoke aromas compared to filtered wines and lower in mixed berry and stone fruit aromas compared to the filtered wines, but only after two months in bottle. Cross flow filtration was found to have a stabilizing effect on the sensory profile of both wines. For both red and white wines, there were significant changes in color and phenolic profile with filtration, but it is not clear, especially for red wines, that the changes in phenolic compound concentration were large enough to be detected sensorially.The transfer of must, juice, and wine is a necessary process in vinification at various points from grape receiving through bottling. Pumps are among the most important pieces of equipment used to move wine from one place to another in commercial wineries. However, there has been a general lack of systematic data generated to assess the effect of pumping on the chemical and sensory properties of wine. These effects, if found, could be due to oxygen pickup during pumping, or some other mechanism of converting mechanical energy to changes in wine composition. To investigate this, a white wine blend and a red wine blend were pumped through a closed loop system at two different run times. Three different pumps were used in the experiment, a centrifugal pump, a flexible impeller pump, and a progressive cavity pump. This resulted in six treatments each for the white and red wines. The entire experiment was carried out in duplicate. A full sensory descriptive analysis panel was conducted on the wines using a ballot-trained panel. UV-VIS spectrophotometery and the Adams-Harbertson assay were used to determine color and phenolic content of the pumped and unpumped wines, respectively. Panelists were not able to differentiate pumped wines from the control, and additionally progressive cavity, flexible impeller, or centrifugal pumped wines from each other. Although statistically significant color differences were found between red wine treatments, these differences were less than 2% and no statistically significant phenolic differences were observed. Oxygen pickup was observed in the progressive cavity pump treatment, but relatively little was observed in the flexible impeller or centrifugal pump treatments. In summary, pumping caused little to no chemical or sensory changes in the experimental wines.

Download or read book Understanding Wine Chemistry written by Andrew L. Waterhouse and published by John Wiley & Sons. This book was released on 2024-05-16 with total page 565 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding Wine Chemistry Understand the reactions behind the world’s most alluring beverages The immense variety of wines on the market is the product of multiple chemical processes – whether acting on components arising in the vineyard, during fermentation, or throughout storage. Winemaking decisions alter the chemistry of finished wines, affecting the flavor, color, stability, and other aspects of the final product. Knowledge of these chemical and biochemical processes is integral to the art and science of winemaking. Understanding Wine Chemistry has served as the definitive introduction to the chemical components of wine, their properties, and their reaction mechanisms. It equips the knowledgeable reader to interpret and predict the outcomes of physicochemical reactions involved with winemaking processes. Now updated to reflect recent research findings, most notably in relation to wine redox chemistry, along with new Special Topics chapters on emerging areas, it continues to set the standard in the subject. Readers of the second edition of Understanding Wine Chemistry will also find: Case studies throughout showing chemistry at work in creating different wine styles and avoiding common adverse chemical and sensory outcomes Detailed treatment of novel subjects like non-alcoholic wines, non-glass alternatives to wine packaging, synthetic wines, and more An authorial team with decades of combined experience in wine chemistry research and education Understanding Wine Chemistry is ideal for college and university students, winemakers at any stage in their practice, professionals in related fields such as suppliers or sommeliers, and chemists with an interest in wine.