Academic literature on the topic 'Red wines and total acidity'
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Journal articles on the topic "Red wines and total acidity"
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Rajkovic, Milos, and Ivana Sredovic. "The determination of titratable acidity and total tannins in red wine." Journal of Agricultural Sciences, Belgrade 54, no. 3 (2009): 223–46. http://dx.doi.org/10.2298/jas0903223r.
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Titration acidity and content of total tannins in mass-market red wines are analyzed in this paper. The content of total acids in wine, expressed through wine acid, was analyzed by potentiometric titration on 7.00 pH value. According to titratable acidity in analyzed wines, all wines (only) with analyzed parameters according to Regulations about wine quality. The analysis of differential potentiometric curves shows that these curves can give the answer to the question if non organic substances, amino groups and phenols are present in wine in large quantity, as they are always present in wine. However it doesn't give the clear answer which substances are present in analyzed samples. The answer to this question can be received only by the method of ionic chromatography. The content of total tannins shows short time of storage in wine cellars so wine wasn't stored long enough, i.e. they are commercial wines made for mass market production and consumption. Although they have less content of total tannin materials of given values, wine taste gives the correlation with other polyphenol materials that only give odour, aroma and 'bouquet' to wine. The relative error of mean value is very low which indicates the reproduction of results and reliability of the method of determination of total tannins in red wine.
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Stein, Tiago, Ivan Ricardo Carvalho, Vinícius Jardel Szareski, et al. "Quality of Cabernet Sauvignon Wines Determined by the Variability of Climatic Attributes." Journal of Agricultural Science 10, no. 8 (2018): 380. http://dx.doi.org/10.5539/jas.v10n8p380.
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Essential to understand the dynamics responsible for the quality of red wines, the objective of revealing the physico-chemical and climatologic relationships that determine the quality of Cabernet Sauvignon wines. The experiment was carried out in the municipality of Dom Pedrito, Rio Grande do Sul, Brazil, in the agricultural crop of 2016. The experiment was conducted in a randomized block design where the treatments corresponded to nine microvinifications arranged in three replicates. The concentration of total polyphenols in Cabernet Sauvignon red wines is associated with anthocyanins, indices of absorbances of 420 and 520, as well as total acidity. However, the tannins are directly proportional to the total acidity of the wine. Environmental conditions with high rainfall, minimum oscillations in thermal amplitude and incident solar radiation tend to increase the hydrogenionic potential and the absorbance indices of 420 (yellow) and 620 (bluish) red wines of Cabernet Sauvignon. The thermal amplitude was preponderant to elevate levels of anthocyanins in Cabernet Sauvignon wines.
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Yoncheva, Tatyana, Mehmet Gülcü, and Elka Kóňová. "Comparative Study of the Phenolic Complex, the Resveratrol Content and the Organoleptic Profile of Bulgarian Wines." Acta Horticulturae et Regiotecturae 21, no. 2 (2018): 36–41. http://dx.doi.org/10.2478/ahr-2018-0009.
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Abstract A comparative study of the phenolic complex, the resveratrol content, the antioxidant activity and the organoleptic profile of Bulgarian wines from the local vine varieties Dimyat, Pamid, Gamza and from the hybrid varieties Plevenska rosa, Storgozia, Kaylashki rubin was carried out. Differences in the chemical composition and tasting characteristics of the experimental wines were identified. As for the white wines, Dimyat had higher sugar-free extract and titratable acidity, while concerning the red ones, Storgozia and Kaylashki rubin showed higher rates. The trans-resveratrol amount in the red wines was significantly higher compared to the white ones, as the samples from the red local varieties had a higher content than the hybrid varieties. Difference in the phenolic composition of the wines was also found. Gamza wine had the highest concentration of total phenolic compounds, total flavonoids and catechin. Storgozia sample contained the highest rates of monomeric anthocyanins and epicatechin. Pamid revealed the lowest concentrations of all analyzed phenolic components except catechin. The red wines had better antioxidant features than the white ones. From the red wines, the highest and the lowest activity were reported in the local varieties – Gamza and Pamid, respectively. There was no strict correlation between the effects of the studied phenolic components on the wine organoleptic profile.
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Campbell-Sills, Hugo, Mariette El Khoury, Marine Gammacurta, et al. "Two different Oenococcus oeni lineages are associated to either red or white wines in Burgundy: genomics and metabolomics insights." OENO One 51, no. 3 (2017): 309. http://dx.doi.org/10.20870/oeno-one.2017.51.4.1861.
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<p style="text-align: justify;"><em>Oenococcus oeni</em> is the bacterium most often associated with spontaneous malolactic fermentation (MLF) of wine. During MLF, malic acid is transformed into lactic acid and several metabolites are modified, modulating wine’s total acidity and improving its sensory properties. Previous works have suggested that certain genetic groups of <em>O. oeni</em> strains are associated to different kinds of products. In the present study we have spotted two groups of strains isolated mainly from Burgundy wines, one associated to red wines and the other to white wines. Sequencing 14 genomes of red and white wine strains revealed that they share a common ancestor that probably colonised two different substrates –red and white wine-associated environments–, diverging over time and disseminating to various regions. Their capacity to perform MLF and modify the volatile profile of wine was determined by fermenting a chardonnay wine and analysing its volatile fraction with a non-targeted metabolomics approach by GC-MS. The strains had a different impact on the volatile composition depending on their group of origin. These results show for the first time a correspondence between the product of origin of the strains and the volatile profile of the wines they produce. Furthermore, the genetic features that might be implied in these different phenotypes are examined.</p>
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Wohlfahrt, Yvette, Claus-Dieter Patz, Dominik Schmidt, Doris Rauhut, Bernd Honermeier, and Manfred Stoll. "Responses on Must and Wine Composition of Vitis vinifera L. cvs. Riesling and Cabernet Sauvignon under a Free Air CO2 Enrichment (FACE)." Foods 10, no. 1 (2021): 145. http://dx.doi.org/10.3390/foods10010145.
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Challenges of climate change on the future grape and wine production are widely discussed in science and in the wine industry with the goal to maintain a consistent must and wine quality in the future. Therefore, the effect of elevated CO2 (eCO2)—as one of the relevant greenhouse gases jointly responsible for a changing climate—was investigated concerning the composition of must and wine made of two grapevine cultivars V. vinifera L. cvs. Riesling and Cabernet Sauvignon within the established VineyardFACE (Free-Air Carbon dioxide Enrichment) experiment. Must and wine analysis were conducted in three consecutive years (2014–2016) by analyzing standard must and wine parameters, e.g., total soluble solids (TSS), pH, total acidity (TA), organic acids (e.g., tartaric acid, malic acid, shikimic acid, citric acid, volatile acid and gluconic acid) or total phenolics (TP). Also, for both cultivars CIELab coordinates (L* for lightness, a* as green/red and b* as blue/yellow components) were used to test colour in young white and red wines. Additionally, total anthocyanins and monomeric indices were analyzed for young wines of the red cultivar Cabernet Sauvignon. With marginal differences between CO2 treatments, the composition of must and young wines was not found to be negatively influenced by an eCO2 concentration.
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Karamanidou, Asimenia, Stamatina Kallithraka, and Efimia Hatzidimitriou. "Fining of red wines: effects on their analytical and sensory parameters." OENO One 45, no. 1 (2011): 47. http://dx.doi.org/10.20870/oeno-one.2011.45.1.1481.
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<p style="text-align: justify;"><strong>Aim</strong>: The aim of the present study was to examine the influence of protein fining on selected quality parameters of wines made from indigenous Hellenic red grape varieties.</p><p style="text-align: justify;"><strong>Methods and Results</strong>: Three different commercial hydrolyzed gelatins and egg albumin were added to two young red wines at three concentrations commonly used in winemaking. The cultivars selected were Hellenic native <em>V. vinifera</em> species used for the production of high quality Appellation of Origin wines (Agiorgitiko and Xinomavro). All the quality parameters studied (anthocyanin concentration, color intensity and hue, ionization degree, total phenolic content, DPPH radical scavenging activity, tannin and polysaccharide concentration, gelatin and HCl indexes, as well as individual phenolic content) were significantly decreased after the addition of the fining agents. The decrease observed was mainly dependent on grape variety, which genetically determines the wine’s phenolic composition, and to a lesser extent on the fining agent used and the dosage applied. In general, treated wines obtained better scores in sensory analysis as compared to untreated ones, although statistically significant differences were only obtained in the Agiorgitiko wine regarding color intensity and hue, acidity, balance, aftertaste, and overall impression.</p><p style="text-align: justify;"><strong>Conclusion</strong>: Wine quality parameters after fining were mainly influenced by the wine’s initial phenolic composition, which is determined mostly by grape variety.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The outcomes of such study might be of practical interest to winemakers since they could optimize red wine production technology by selecting the appropriate fining agent according to the specific phenolic profiles of the produced wines and thus improve their quality.</p>
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Kučerová, Jindřiška, and J. Široký. "Study of changes organic acids in red wines during malolactic fermentation." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 59, no. 5 (2011): 145–50. http://dx.doi.org/10.11118/actaun201159050145.
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The aim of this contribution is to be able to describe the movement of organic acids in red wine during malolactic fermentation. Wines from Znojmo wine region were represented by varieties of Svatovavřinecké (Saint Laurent), Rulandské modré (Pinot Noir), Zweigeltrebe, Frankovka (Lemberger) and Dornfelder. The grapes went through the same way of wine making and after completion of alcoholic fermentation were inoculated with pure culture of lactic acid bacteria Oenococcus oeni. Samples were taken for chemical analysis during biodegradation of acids within the range of 2 to 4 days and they were measured using a device WineScan FT 120. Chemical analysis detected changes in the concentrations of the following parameters: total acidity, lactic, malic, tartaric and citric acids. The total content of acids statistically significantly (P = 0.05) differed only between samples of Svatovavřinecké T 66 and Zweigeltrebe T 2.The differences of average mass concentrations of lactic, malic and citric acids were not statistically relevant. Nevertheless, statistically relevant difference in the concentration of tartaric acid from all other wines was detected in a sample of SV T 66 which also reached the highest average value (5.18 g/l).
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Bokkhim, Huma, Praksha Neupane, Smita Gurung, and Rojeena Shrestha. "Encapsulation of Saccharomyces cerevisiae in alginate beads and its application for wine making." Journal of Food Science and Technology Nepal 10 (November 30, 2018): 18–23. http://dx.doi.org/10.3126/jfstn.v10i0.19631.
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A study was carried out on encapsulation of wine yeast (Saccharomyces cerevisiae) and its use in wine making compared to free yeast. Rehydrated active dry yeast was encapsulated in a 2% sodium alginate solution, cross linked with different molar concentration of CaCl2 solution (0.1, 0.2, 0.3,0.4 and 0.5M) for 30 minutes. The molar concentration with minimum cell leakage (0.2M) was used for yeast encapsulation. Colony count (CFU/ml) was analyzed for both free yeast (FY) and encapsulated yeast (EY) so as to equilibrate the rate of yeast pitching in wine fermentation. Physico-chemical properties; total soluble solids (T.S.S.), acidity and pH of red and white grapes were analyzed and were found to be 16.4±0.10oBx, 0.38±0.02% and 3.90±0.02 for white grapes and 19±0.15oBx, 0.64±0.01% and 3.1±0.10 for red grapes. During the fermentation process in both wines, a gradual reduction in T.S.S. was noted while an alternate of increase and decrease trend in acidity was noted which finally stabilized after 12 days. The final T.S.S. of wines was not significantly different for yeast types but higher values were noted for red wine (FY, 7.11±0.26 & EY, 7.33±0.19) than for white wine (FY, 6.1±0.10 & EY, 6.2±0.10). Similar trend was noted for final acidity of red wine (FY, 0.83±0.01 & EY, 0.84±0.02%). Though, no significant effect of yeast type on alcohol production was noted, the average alcohol content of red (FY, 13.22±0.26% & EY, 13.72±0.44%) and white (FY, 9.21±0.21% & EY, 9.64±0.38%) wine were found to be significantly different. However, wine prepared from EY was less turbid (Red wine, 95 NTU & White wine, 140 NTU) and had higher clarity (L*) than wine from FY. So, from this study it was concluded that encapsulating wine yeast does not affect its fermenting capability but will aid in production of less turbid wine which will definitely simplify the filtration process.
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Morais, Cristiane Da Silva, Luiza Mariano Leme, Patrícia Valderrama, and Paulo Henrique Março. "Multivariate calibration applied in UV-Vis spectroscopy data to determine total acidity in wines." Revista Brasileira de Pesquisa em Alimentos 6, no. 1 (2015): 70. http://dx.doi.org/10.14685/rebrapa.v6i1.193.
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<p>Classical methods, as titration to evaluate acidity, bring disadvantage to waste generation and mainly time consumption. Therefore, is necessary to develop an alternative methodology for measuring total acidity of wine samples. The Ultraviolet and Visible spectrophotometric technique can be introduced in the industry to monitoring this parameter because it enables rapid and efficient analysis without waste generation. Thereby, in this study were developed multivariate calibration models using the Partial Least Squares (PLS) regression between the UV-Vis spectra of wines and total acidity values determined by the reference method. The figures of merit for the models were Root Mean Squared Error of Calibration (RMSEC), Root Mean Squared Error of Prediction (RMSEP) and correlation coefficient (R). To the white wines, the model obtained showed RMSEC and RMSEP of 5.87 meq L<sup>-1</sup> and 6.58 meq L<sup>-1</sup>, respectively. To the red wines, the model presented RMSEC 0.71 meq L<sup>-1</sup> and RMSEP 6.93 meq L<sup>-1</sup>. Both models presented correlation coefficient of 0.71. A paired t-test showed no significant difference between titration and spectrophotometric methods at a confidence level of 95%. Therefore, the advantages offered by the UV-Vis method are attractive to industrial requirements, suggesting that studies focused on optical methods and multivariate calibration can be interesting and deserve to be observed in further studies.</p><p>&nbsp;</p><p>DOI: 10.14685/rebrapa.v6i1.193</p><p>&nbsp;</p>
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Santoro, Heidi Christine, Danijela Skroza, Anđela Dugandžić, Mladen Boban, and Vida Šimat. "Antimicrobial Activity of Selected Red and White Wines against Escherichia coli: In Vitro Inhibition Using Fish as Food Matrix." Foods 9, no. 7 (2020): 936. http://dx.doi.org/10.3390/foods9070936.
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Five different wines (standard Graševina, macerated Graševina with and without sulfur, rosé, and standard Plavac Mali), all typical Croatian wines, were tested to determine the antimicrobial activity against two Escherichia coli bacterial strains (ATCC® 25922 and ATCC® 8739) in vitro and using sea bass (Dicentrarchus labrax) fillets as food matrix. The chemical composition of wines (pH, acidity, alcohol, total phenolics, anthocyanins, tannins, and sulfur content) and antimicrobial activity (minimal inhibitory concentration (MIC), agar-well diffusion method) were determined. The total phenolic content of the wines ranged from 305–3210 mg gallic acid equivalents per liter (GAE/L), and did not correlate to antimicrobial activity. The two wines with the lowest phenolic content (standard Graševina and rosé) had the lowest MIC values (122 and 429 mg GAE/L). A specific relation between the winemaking process and a particular MIC value was not established. There was also no relation found between the pH value, ethanol content, sulfur, or phenolics in regards to the antimicrobial effect. In fish fillets marinated in wine + water mixture (v/v = 1:1) and inoculated with 7 log colony forming units (CFU)/25 g the growth of bacteria was reduced after three days of storage at 4 °C. Subsequent storage resulted in the growth of bacteria in all samples, with the lowest growth of E. coli ATCC® 25922 in macerated Graševina and E. coli ATCC® 8739 in standard Graševina. All wines showed the capacity to reduce the number and growth of heavily infected sea bass filets, but correlation with specific wine constituents was not found. Taking into account the numerous reactive mechanisms between food and wine, all in vitro studies in controlled laboratory conditions should be further verified in the relevant environment, and additional research is needed to clarify the role of individual wine components in the mechanism of antimicrobial activity.
Dissertations / Theses on the topic "Red wines and total acidity"
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Tôrres, Adamastor Rodrigues. "Determinação da acidez total de vinhos tintos empregando titulações baseadas em imagens digitais." Universidade Federal da Paraíba, 2010. http://tede.biblioteca.ufpb.br:8080/handle/tede/7168.
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Previous issue date: 2010-03-19<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>This work proposes the use of digital images captured by a Webcam for
determination of total acidity in red wines by means of an acid-base titration without
using an external indicator. Digital images present the colour of the emergent
radiation, which is complementary to the radiation absorbed by molecules of
anthocyanines presents in wines. Each image, generated according to RGB system,
yields a matrix of the values of the R, G and B components whose averages define a
the colour value obtained as: 2R ⋅2G ⋅2B. This value was adopted as analytical
response to build titrations curves based on digital images (DIB). For a more precise
localization of the end point, titrations curves were generated on the basis of the
second derivative values of the analytical response. Anthocyanines present different
colours according to medium pH and, from the variation of the colour values of the
images obtained during the titration of the red wines, the end point could be detected
with precision. The official method recommends the use of potenciometric titration for
determination of total acidity in red wines. This method requires a dilution of the
sample before the titration that must be carried out until a fixed value of pH (8.2
8.4). In order to illustrate the feasibility of the proposed method titrations involving the
determination of total acidity in ten red wines samples were carried out. Results were
compared to the ones obtained by potenciometric titration used as reference method.
No statistic difference has been observed between the results by applying the paired
t-test at 95% confidence level. The proposed method yielded results with a better
precision than the official method. These advantageous characteristics are attributed
to the trivariate nature of the measures associated to digital images.<br>Neste trabalho, propõe-se o uso de imagens digitais, capturadas com uma
Webcam, para determinação da acidez total de vinhos tintos por meio de titulação
ácido-base sem a utilização de indicador externo. As imagens digitais apresentam a
cor da radiação emergente que é complementar à da radiação absorvida por
moléculas de antocianinas presentes nos vinhos. Cada imagem, gerada de acordo
com o sistema vermelho-verde-azul (RGB), fornece uma matriz de valores dos
componentes R, G e B cujas médias definem o valor de cor obtido como:
2R ⋅2G ⋅2B. Esse valor foi adotado como resposta analítica para a construção das
curvas de titulação baseadas em imagens digitais (DIB). Para a localização mais
precisa do ponto final, foram geradas as curvas de titulação com base nos valores
da segunda derivada da resposta analítica. As antocianinas apresentam diferentes
cores de acordo com o pH do meio e, a partir das variações do valor de cor das
imagens obtidas durante a titulação dos vinhos tintos, o ponto final pôde ser
detectado com precisão. O método oficial recomenda o uso da titulação
potenciométrica para a determinação da acidez total de vinhos tintos. Este método
requer diluição da amostra antes da titulação que deve ser efetuada até um valor
fixo de pH (8,2-8,4). A fim de ilustrar a viabilidade do método proposto, foram
realizadas titulações envolvendo a determinação da acidez total em dez amostras de
vinhos tintos. Os resultados foram comparados com os obtidos pela titulação
potenciométrica usada como método de referência. Constatou-se que não há
diferença sistemática estatisticamente significativa entre os resultados, aplicando-se
o teste t emparelhado ao nível de 95% de confiança. O método proposto produziu
resultados com uma precisão melhor que a do método oficial. Essas características
vantajosas da titulação DIB são atribuídas à natureza trivariada das medidas
associadas às imagens digitais.
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Fadock, Michael. "Non-Destructive VIS/NIR Reflectance Spectrometry for Red Wine Grape Analysis." Thesis, 2011. http://hdl.handle.net/10214/2827.
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A novel non-destructive method of grape berry analysis is presented that uses reflected light to predict berry composition. The reflectance spectrum was collected using a diode array spectrometer (350 to 850 nm) over the 2009 and 2010 growing seasons. Partial least squares regression (PLS) and support vector machine regression (SVMR) generated calibrations between reflected light and composition for five berry components, total soluble solids (°Brix), titratable acidity (TA), pH, total phenols, and anthocyanins. Standard methods of analysis for the
components were employed and characterized for error. Decomposition of the reflectance data was performed by principal component analysis
(PCA) and independent component analysis (ICA). Regression models were constructed using 10x10 fold cross validated PLS and SVM models subject to smoothing, differentiation, and normalization pretreatments. All generated models were validated on the alternate season using two model selection strategies: minimum root mean squared error of prediction (RMSEP), and the "oneSE" heuristic.
PCA/ICA decomposition demonstrated consistent features in the long VIS wavelengths and NIR region. The features are consistent across seasons. 2009 was generally more variable, possibly due to cold weather affects. RMSEP and R2 statistics of models indicate that PLS °Brix, pH, and TA models are well predicted for 2009 and 2010. SVM was marginally better. The R2 values of the PLS °Brix, pH, and TA models for 2009 and 2010 respectively were: 0.84, 0.58, 0.56 and: 0.89, 0.81, 0.58. 2010 °Brix models were suitable for rough screening. Optimal
pretreatments were SG smoothing and relative normalization. Anthocyanins were well predicted in 2009, R2 0.65, but not in 2010, R2
0.15. Phenols were not well predicted in either year, R2 0.15-0.25. Validation demonstrated that °Brix, pH, and TA models from 2009 transferred to 2010 with fair results, R2 0.70, 0.72, 0.31. Models generated using 2010 reflectance data did not generate models that could predict 2009 data. It is hypothesized that weather events present in
2009 and not in 2010 allowed for a forward calibration transfer, and prevented the reverse calibration transfer. Heuristic selection was superior to minimum RMSEP for transfer, indicating some overfitting in the minimum RMSEP models. The results are demonstrative of a reflectance-composition relationship in the VIS-NIR region for °Brix, pH, and TA requiring additional study and development of further calibrations.
Book chapters on the topic "Red wines and total acidity"
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Tengzhen, Ma, and Han Shunyu. "Winemaking in Cold Regions with Buried Viticulture in China." In Grapes and Wine [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.99614.
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China has a long history of grape cultivation and wine making, and it has grown to be one of the most important countries in terms of grape cultivation, wine production, and wine consumption. According to meteorological and geographical regionalization, China’s wine production area has been divided into 11 regions, the majority of which are located in cold and mid-temperate regions in northern China, where vines must be buried in winter and unearthed in spring. In China, the main cultivated grape varieties are similar, with the red variety accounting for more than 80% of the total, while the white variety represents just 20%. Currently, Cabernet Sauvignon is the most widely planted variety, but Marselan, another red variety, have recently shown good prospects. Wild grape species such as Vitis amurensis, Vitis davidii, and Vitis quinquangularis are widely planted in northern and southern China because of their good resistance to local climate. This chapter highlights some common wild grape varieties in China, as well as the wines made from them. Also, some winemaking pretreatment techniques are reported.
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Bethke, Craig M. "Acid Drainage." In Geochemical Reaction Modeling. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195094756.003.0027.
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Acid drainage is a persistent environmental problem in many mineralized areas. The problem is especially pronounced in areas that host or have hosted mining activity (e.g., Lind and Hem, 1993), but it also occurs naturally in unmined areas. The acid drainage results from the weathering of sulfide minerals that oxidize to produce hydrogen ions and contribute dissolved metals to solution. These acidic waters are toxic to plant and animal life, including fish and aquatic insects. Streams affected by acid drainage may be rendered nearly lifeless, their stream beds coated with unsightly yellow and red precipitates of oxy-hydroxide minerals. In some cases, the heavy metals in acid drainage threaten water supplies and irrigation projects. Where acid drainage is well developed and extensive, the costs of remediation can be high. In the Summitville, Colorado district (USA), for example, efforts to limit the contamination of fertile irrigated farmlands in the nearby San Luis Valley and protect aquatic life in the Alamosa River will cost an estimated $100 million or more (Plumlee, 1994a). Not all mine drainage, however, is acidic or rich in dissolved metals (e.g., Ficklin et al., 1992; Mayo et al., 1992; Plumlee et al., 1992). Drainage from mining districts in the Colorado Mineral Belt ranges in pH from 1.7 to greater than 8 and contains total metal concentrations ranging from as low as about 0.1 mg/kg to more than 1000 mg/kg. The primary controls on drainage pH and metal content seem to be (1) the exposure of sulfide minerals to weathering, (2) the availability of atmospheric oxygen, and (3) the ability of nonsulfide minerals to buffer acidity. In this chapter we construct geochemical models to consider how the availability of oxygen and the buffering of host rocks affect the pH and composition of acid drainage. We then look at processes that can attenuate the dissolved metal content of drainage waters. Acid drainage results from the reaction of sulfide minerals with oxygen in the presence of water. As we show in this section, water in the absence of a supply of oxygen gas becomes saturated with respect to a sulfide mineral after only a small amount of the mineral has dissolved.
Conference papers on the topic "Red wines and total acidity"
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DOBREI, Alin, Alina Georgeta DOBREI, Eleonora NISTOR, Sorin STANCIU, Mihaela MOATĂR, and Florin SALA. "SUSTAINABILITY OF GRAPEVINE PRODUCTION THROUGH MORE EFFICIENT SYSTEMS OF SOIL MAINTENANCE AND AGRO-BIOLOGICAL INDICATORS." In Rural Development 2015. Aleksandras Stulginskis University, 2015. http://dx.doi.org/10.15544/rd.2015.022.
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Tillage practices in viticulture are very important, with major effects on quantitative and qualitative production, on vines phenology and stages of growth. In this study the aim was to identify the most appropriate vineyard floor management, located on flat land or mild slopes, with medium or high soils fertility. The research was carried out during 2011–2013 in the vineyard of the BUASVM Didactic Station from Timisoara and focusing exclusively on several variants of soil maintenance in order to replace the need for manual labor. Leaf area was estimated by concentric circles method and sugar concentration was evaluated by refractometry. Total acidity in must and wine was determined by titration. Grape yield was estimated by bunches counting and weighing, for each variety and productive potential (kg ha-1) was appreciated by multiplying the average yield per vine with the number of vines per hectare. Statistical analysis was performed using GraphPad Prism 6. Performance of Burgundy variety for superior red wines group and Silvania table grape variety – with a medium ripening, were analyzed in the experiment. For both Burgundy and Silvania varieties the sixth variant (V6–bare soil by tillage middles row (tractor and rotary hoe)/rotary hoe undervine (tractor and adjustable offset rotary tiller) registered the highest grape yield during the research. The lowest grape yield fulfils to the seventh variant of vineyard floor management. Burgundy variety had the average must sugar content of 195 ± 4.27 g l-1 and that of the leaf area of 7.09 ± 0.58 m2 while in Silvania variety the average of grape must acidity was 4.66 ± 0.35 g l-1 H2SO4 and the leaf area of 7.42 ± 0.51 m2/vine. Between must sugar content and leaf area, in Burgundy and Silvania variety has been established a significant positive linear correlation (r = 0.94 ***) and (r = 0.88 **; p <0.001) respectively, variables being virtually indistinguishable.
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Watson, Simon A. G., Victor W. Wong, Darrell Brownawell, and Scott P. Lockledge. "Controlling Lubricant Acidity With an Oil Conditioning Filter." In ASME 2009 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/ices2009-76100.
Full textAbstract:
In modern diesel engines, acidity generally determines the lubricant drain interval. To control acidity, lubricant suppliers incorporate detergent additives to neutralize acids that accumulate in the oil via exhaust blow-by and base-stock oxidation. However, formulations that meet the most recent diesel lubricant classification specifications typically contain lower levels of detergent since this additive contributes to ash that fouls emissions aftertreatment systems. This study explores a novel approach to lubricant acid control as a potential means to reduce additive requirements or increase oil drain interval. The authors investigate the performance of an innovative oil filter that releases no additives into the lubricant, yet enhances the acid control function typically performed by detergent and dispersant additives. The filter chemically conditions the crankcase oil during engine operation by sequestering acidic compounds derived from engine combustion and lubricant degradation. Long duration heavy-duty diesel engine tests show that the filter reduces both the rate of Total Base Number (TBN) decline and the rate of Total Acid Number (TAN) increase by a factor of two. Analysis by Fourier transform infra-red (FTIR) spectroscopy also indicates that lubricant oxidation may be lowered. In addition, these results suggest a reduction in engine wear. These results imply that lower lubricant additive levels in combination with this novel oil filter may be used to reduce ash accumulation in diesel aftertreatment systems, while maintaining adequate engine protection. The results also indicate that the engine operator may use this oil filter with a state-of-the art lubricant to lengthen oil change intervals.