[PDF] The Effect Of Ph And Ethanol On The Astringent Sub Qualities Of Red Wine And The Implications For Optimum Grape Maturity eBook

Author : Palmina De Miglio
Publisher :
Page : pages
File Size : 31,45 MB
Release : 2004
Category :
ISBN :

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The first objective of this study was to identify appropriate sensory descriptors to assess the astringent sub-qualities of red wine. The influence of pH and ethanol on the sensation of astringency in red wine was evaluated, using a de-alcoholized red wine. A portion of the wine was adjusted to the pH values of 3.2, 3.4, 3.6 and 3.8, and another portion was adjusted to ethanol concentrations of 0%, 6%, 12%, and 15%. In addition, the pH 3.4 and 3.6 treatments were adjusted to an ethanol concentration of 12% and 15% all wines were then assessed sensorially and seventeen terms were identified, through panel discussion, to describe the mouth-feel and taste qualities: velvet, aggressive, silk/satin, dry, fleshy, unripe, pucker viscosity, abrasive, heat, chewy, acidity, grippy/adhesive, bitter, balance, overall astringency, and mouth-coat. Descriptive analysis profiling techniques were used to train the panel and measure the intensity of these attributes. It was found that decreasing pH values (averaged across all ethanol concentrations) showed an increase in the overall astringency of the wine. The combined treatments of ethanol and pH, real wine parameters (pH 3.4 and 3.6; 12% and 15% ethanol) did not have an effect on the perception of the astringent sub-qualities of the wine. A time intensity study was also included using the pH and ethanol adjusted wines, which showed that as the ethanol level of the wines increased so did the time to maximum intensity. The second objective was to identify appropriate sensory descriptors to evaluate the influence of grape maturity and maceration technique (grape skin contact) on the astringency sub-qualities of red vinifera wines from Niagara. The grapes were harvested across two dates, representing an early harvest and a late harvest. A portion of the Cabernet Sauvignon grapes wine was divided into three maceration treatments of oneweek maceration, standard two-week maceration, three-week maceration, and MCM. Another portion of both the early and late harvest Cabernet Sauvignon grapes were chaptalized to yield a final ethanol concentration of 14.5%. The wines were assessed sensorially and thirteen terms were identified, through panel discussion, to describe the mouth-feel and taste qualities: carbon dioxide, pucker, acidity, silk/chamois, dusty/chalky/powdery, sandpaper, numbing, grippy/adhesive, dry, mouthcoat, bitter, balance and, overall astringency. Descriptive analysis techniques were used to train the panel and measure the intensity of these attributes. The data revealed few significant differences in the mouth-feel of the wines with respect to maturity; which included differences in overall astringency and balance. There were varietal differences between Cabernet Sauvignon, Cabernet Franc, and Pinot Noir and differences for Cabernet Sauvignon wines due to the length and manner of maceration and as a result of chaptalization. Statistical analysis revealed a more complex mouth-feel for the Pinot Noir wines; and an increase in the intensity of the astringent sub-qualities as a result of the addition of sugar to the wines. These findings have implications for how processing decisions, such as optimum grape maturity and vinification methods may affect red wine quality.

Author : Giuseppe Spano
Publisher : Frontiers Media SA
Page : 233 pages
File Size : 27,82 MB
Release : 2017-03-28
Category :
ISBN : 2889451216

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During spontaneous food/beverage fermentations, the microbiota associated with the raw material has a considerable importance: this microbial consortium evolves in reason of the nutrient content and of the physical, chemical, and biological determinants present in the food matrix, shaping fermentation dynamics with significant impacts on the ‘qualities’ of final productions. The selection from the indigenous micro-biodiversity of ‘virtuous’ ecotypes that coupled pro-technological and biotechnological aptitudes provide the basis for the formulation of ‘tailored’ starter cultures. In the fermenting food and beverage arena, the wine sector is generally characterized by the generation of a high added value. Together with a pronounced seasonality, this feature strongly contributes to the selection of a large group of starter cultures. In the last years, several studies contributed to describe the complexity of grapevine-associated microbiota using both culture-dependent and culture-independent approaches. The grape-associated microbial communities continuously change during the wine-making process, with different dominances that correspond to the main biotechnological steps that take place in wine. In order to simplify, following a time trend, four major dominances can be mainly considered: non-Saccharomyces, Saccharomyces, lactic acid bacteria (LAB), and spoilage microbes. The first two dominances come in succession during the alcoholic fermentation: the impact of Saccharomyces (that are responsible of key enological step of ethanol production) can be complemented/integrated by the contributions of compatible non-Saccharomyces strains. Lactic acid bacteria constitute the malolactic consortium responsible of malolactic fermentation, a microbial bioconversion often desired in wine (especially in red wine production). Finally, the fourth dominance, the undesired microbiota, represents a panel of microorganisms that, coupling spoilage potential to the resistance to the harsh conditions typical of wine environment, can cause important economic losses. In each of these four dominances a complex microbial biodiversity has been described. The studies on the enological significance of the micro-biodiversity connected with each of the four dominances highlighted the presence of a dichotomy: in each consortia there are species/strains that, in reason of their metabolisms, are able to improve wine ‘qualities’ (resource of interest in starter cultures design), and species/strains that with their metabolism are responsible of depreciation of wine. Articles describing new oenological impacts of yeasts and bacteria belonging to the four main categories above mentioned (non-Saccharomyces, Saccharomycetes, lactic acid bacteria, and spoilage microbes) are welcome. Moreover, in this Research Topic, we encourage mini-review submissions on topics of immediate interest in wine microbiology that link microbial biodiversity with positive/negative effects in wine.

Author : Maria R. Kosseva
Publisher : Academic Press
Page : 758 pages
File Size : 38,19 MB
Release : 2016-11-01
Category : Technology & Engineering
ISBN : 0128010347

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Science and Technology of Fruit Wine Production includes introductory chapters on the production of wine from fruits other than grapes, including their composition, chemistry, role, quality of raw material, medicinal values, quality factors, bioreactor technology, production, optimization, standardization, preservation, and evaluation of different wines, specialty wines, and brandies. Wine and its related products have been consumed since ancient times, not only for stimulatory and healthful properties, but also as an important adjunct to the human diet by increasing satisfaction and contributing to the relaxation necessary for proper digestion and absorption of food. Most wines are produced from grapes throughout the world, however, fruits other than grapes, including apple, plum, peach, pear, berries, cherries, currants, apricot, and many others can also be profitably utilized in the production of wines. The major problems in wine production, however, arise from the difficulty in extracting the sugar from the pulp of some of the fruits, or finding that the juices obtained lack in the requisite sugar contents, have higher acidity, more anthocyanins, or have poor fermentability. The book demonstrates that the application of enzymes in juice extraction, bioreactor technology, and biological de-acidification (MLF bacteria, or de-acidifying yeast like schizosaccharomyces pombe, and others) in wine production from non-grape fruits needs serious consideration. Focuses on producing non-grape wines, highlighting their flavor, taste, and other quality attributes, including their antioxidant properties Provides a single-volume resource that consolidates the research findings and developed technology employed to make wines from non-grape fruits Explores options for reducing post-harvest losses, which are especially high in developing countries Stimulates research and development efforts in non-grape wines

Author : Michael O'Mahony
Publisher : Routledge
Page : 518 pages
File Size : 37,35 MB
Release : 2017-11-22
Category : Technology & Engineering
ISBN : 1351416898

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Sensory Evaluation of Food: Statistical Methods and Procedure covers all of the basic techniques of sensory testing, from simple discrimination tests to home use placements for consumers. Providing a practical guide to how tests are conducted, the book explores the fundamental psychological and statistical theories that form the basis and rationale for sensory test design. It also demonstrates how statistics used in sensory evaluation can be applied in integrated applications in the context of appropriate sensory methods, as well as in stand-alone material in appendices. Offering a balanced view of diverse approaches, this is an essential guide for industry professionals and students.

Author : Anton Prajitna
Publisher :
Page : 244 pages
File Size : 35,98 MB
Release : 2006
Category : Grapes
ISBN :

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Abstract: This study investigated the effect of cluster thinning on the quality and nutraceutical content of 'Chambourcin', 'Pinot noir' and 'Cabernet franc' wine grape berries and wines. In addition, this study investigated SO2 interference on wine nutraceutical content determination. In experiment 1, three vintages of Chambourcin and one vintage of Pinot noir crop level treated wines were evaluated for their composition, anthocyanin, total phenolic, antioxidant and total resveratrol content. Cluster thinning did not affect basic wine composition except pH. Cluster thinning, however, increased the total anthocyanins, total phenolics, and antioxidant capacity. Cluster thinning also increased the total resveratrol level in Chambourcin but not in Pinot noir wines. In experiment 2, we evaluated the effect of cluster thinning on yield parameters, vine growth, fruitfulness, canopy parameters, composition, anthocyanins, total phenolics and antioxidant capacity of 'Chambourcin', 'Pinot noir' and 'Cabernet franc' berries. We found that reponses cluster thinning treatments appear to be confounded with cold injury. Cluster thinning reduced yield in one out of two years of 'Chambourcin' and 'Pinot noir' vines. Cluster thinning increased cluster weight of Chambourcin but not Pinot noir and Cabernet franc. Cluster thinning decreased cropload of Chambourcin and one year of 'Pinot noir' vines. 'Pinot noir' vines under low crop level treatments had the most clusters/vine count prior to cluster thinning in 2004. Cluster thinning increased the anthocyanins, total phenolics and antioxidant capacity of Chambourcin berries linearly independent of harvest date. In experiment 3, we evaluated the extent of sulfite content interference on antioxidant determination (FRAP and ABTS assay) in red and white wines. Addition of SO2 up to 200 mg/L increased antioxidant capacity significantly. Addition of 100 mg/L SO2 generated on average 6.6 % and 64 % increase in antioxidant capacity for red and white wines, respectively indicating the extent of interference was much more pronounced in white compared to red wines.

Author : Andrew G. Reynolds
Publisher : Woodhead Publishing
Page : 0 pages
File Size : 43,28 MB
Release : 2010-10-14
Category : Technology & Engineering
ISBN : 9781782421443

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Many aspects of both grape production and winemaking influence wine sensory properties and stability. Progress in research helps to elucidate the scientific basis of quality variation in wine and suggest changes in viticulture and oenology practices. The two volumes of Managing wine quality review developments of importance to wine producers, researchers, and students. The focus is on recent studies, advanced methods and likely future technologies. Volume 1 opens with chapters reviewing current understanding of wine aroma, colour, taste and mouthfeel. Part two focuses on the measurement of grape and wine properties. Topics covered include instrumental analysis of grape, must and wine, sensory evaluation and wine authenticity and traceability. The effects of viticulture technologies on grape composition and wine quality attributes are the subject of part three. Terroir, viticultural and vineyard management practices, fungal contaminants and grape processing equipment are among the areas discussed. Volume 2 opens with chapters reviewing the impact of different winemaking technologies on quality. Topics covered include yeast and fermentation management, enzymes, ageing on lees, new directions in stabilisation, clarification and fining of white wines and alternatives to cork in wine bottle closures. Managing wine sensory quality is the major focus of part two. Authors consider issues such as cork taint, non-enzymatic oxidation and the impact of ageing on wine flavour deterioration. The volume concludes with chapters on the management of the quality of ice wines and sparkling wines. Reviews current understanding of wine aroma, colour, taste and mouthfeel Details the measurement of grape and wine properties through instrumental analysis, must and wine, and sensory evaluation Reviews the impact of different technologies on wine quality

Author : Marcos Soto-Hernández
Publisher : BoD – Books on Demand
Page : 458 pages
File Size : 24,58 MB
Release : 2017-03-15
Category : Science
ISBN : 9535129570

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Phenolic compounds as a large class of metabolites found in plants have attracted attention since long time ago due to their properties and the hope that they will show beneficial health effects when taken as dietary supplements. This book presents the state of the art of some of the natural sources of phenolic compounds, for example, medicinal plants, grapes or blue maize, as well as the modern methods of extraction, quantification, and identification, and there is a special section discussing the treatment, removal, and degradation of phenols, an important issue in those phenols derived from the pharmaceutical or petrochemical industries.