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Chemical characterization of bottled sweet wines from the Canary Islands (Spain)
Abstract
Samples of sweet wines from the Canary Islands belonging to the Denominations of Origin of La Palma and Lanzarote islands were analysed in relation to chemical parameters. The main chemical parameters analysed demonstrated that these wines fulfil all the legal requirements, since the content of all components tested falls below the maximum concentration admissible. Applying techniques of multivariate analysis (principal component, discriminant and cluster analysis), a complete differentiation could be achieved between the wines according to the island of production using only alcohol degree and isobutanol, which are chemical parameters related to the elaboration process.
... The variation coefficients have relative normal values, except the variation coefficient associate to the Free sugar parameter (39,2%), who passed the normal limit. The values of variation coefficients of the others parameters, for example: Alcohol (5,7 %), Total dry extract (8,4 %), Total acidity (7,89 %) and Total SO 2 (10,68 %), were in normal limits [4,9]. In the second The parameters' values are placed in admitted limits for the dry wine and superior wines category. ...
There have been analysed the physical and chemical characteristics (d 20 , alcohol % vol., total dry extract mg/l, free sugar g/l, unreducing extract g/l, total acidity g/l C 4 H 6 O 6 , free SO 2 mg/l, total SO 2 mg/l) definitive for the wine quality made from the Sauvignon grapes'variety, in three successive years:2004, 2005 and 2006.The climatic peculiarities of the mentioned years, determined the appearance of some quality statistic differences, as follows: d 20 20 decreased very significantly in 2005 and 2006 comparative to 2004, the quantity of alcohol increased significant in 2005 and 2006 comparative to 2004, free sugar decreased very significantly in 2005 and 2006 comparative to 2004, the total dry extract and unreducing extract decreased very significant in 2005 and 2006 against 2004 and the total SO 2 content was very significantly lower in 2005 and 2006 against 2004. There have been observed no differences between the annual crops, concerning the parameters: total acidity and free SO 2. Conclusevely, the wine from 2004 was demidry, more sulfiteted, comparative with the wines from 2005 and 2006.
... There have been analysed the following quality parameters of the wine: d 20 20 (picnometric method STAS 6182/8-71), alcohol % vol. (picnometric method STAS 6182/6-70), total dry extract mg/l (densimetric method STAS 6182/9-80), free sugar g/l (iodometric method STAS 6182/18-81), unreducing extract g/l, total acidity g/l C 4 H 6 O 6 (titrimetric method STAS 6182/1-79), free SO 2 mg/l (iodometric method STAS 6182/13-72) and total SO 2 mg/l (iodometric method STAS 6182/13-72) [2,3,4,7]. The obtained results were statistical processed using the professional program COHORT. ...
There have been analysed the physical and chemical characteristics (d 20 , alcohol % vol., total dry extract mg/l, free sugar g/l, unreducing extract g/l, total acidity g/l C 4 H 6 O 6 , free SO 2 mg/l, total SO 2 mg/l) definitive for the wine quality made from the White Feteasca grapes'variety, in three successive years: 2004,2005 and 2006. The climatic peculiarities of the forenamed years, determined the appearance of some quality statistic differences, as follows: d 20 20 diminished significantly in 2006 comparative to the precedents years, the quantity of alcohol increased distinctly significant in 2006 comparative to 2004 and 2005, the total dry extract and unreducing extract diminished distinctly significant in 2005 against 2004, total acidity diminished very significantly in 2006 against 2004, respective 2005 and the total SO 2 content was significantly and very significantly lower in 2006 against 2004, respective 2005. There have been observed no differences between the annual crops, concerning the parameters: free sugar and free SO 2. Conclusevely, the wine from 2006 was stronger, more dry and less sulfiteted, comparative with wines from 2004 and 2005.
Nine phenolic compounds (gallic acid, (+)catechin, vanillic and caffeic acid, p-coumaric acid, resveratrol, myricetin, quercitrin and quercetin) of fourteen Eger (Hungarian) young red wines were investigated using high-performance liquid chromatography in order to obtain data on the 2003 vintage. The grapes were harvested at different sites of the wine-district, vinified with same technology, but stored under different conditions (glass holder or 5-10 years old oak barrel). Same varietal wines originating from different sites of Eger wine-region showed considerable alterations in some phenolic components, and we found distinction in polyphenol content of different varietal wines originating from the same harvesting site. Cluster analysis was performed to acquire information about the similarity among the measured wines. Our study provides new data of polyphenol composition for Eger (Hungary) pure varietal red wines, and the results contribute to better identification of Hungarian red wines on the basis of geographical location.
Three-year-old ‘Cardinal’ and ‘Pinot noir’ vines were grown from véraison to fruit maturity in a stationary and rotating phytotron at high (30°C) and low (20°C) day temperatures in combination with both high (>2,500 ft-c) and low (< 1,200 ft-c) average light intensities. Night temperature (6 PM to 6 AM) was 15°C in all treatments. Berries were collected at weekly intervals and analyzed for various constituents.
Low temperature usually resulted in increased berry weight, total acidity, and malate, and in decreased pH, arginine, proline, and total N in the berry juices, as compared to fruits grown at high temperature. The concentrations of total soluble solids and tartrate in the fruits generally did not significantly differ with temperature. Low light intensity at both high and low temperatures generally resulted in reduced berry weight, total soluble solids, pH, and proline, and in increased levels of total acidity, malate, arginine, and total N in the berry juices compared to grapes grown at high light intensity at the same room temperature. The concentration of arginine was highly correlated with the level of total N in the fruits of both cultivars.
The effect of temperature on development of ‘Cabernet Sauvignon’ berries was examined in growth cabinets beginning 3 weeks after flowering and terminating 6 weeks after the start of stage III. High temperature, 35/30°C, reduced the amount and duration of berry growth during stage I; it lengthened stage II by inhibiting the onset of stage III. Final berry size was irreversibly reduced by high temperature during stage I. The duration of stage II was also lengthened by lowering the day/night temperature during stage I from 25/20 to 18/13°C. Maximum berry size was attained most rapidly at the intermediate and most slowly at high temperature. Generally, stages I and II were more sensitive to temperature than stage III.
Final berry weight was lowest at 35/30°C. The concentration of total soluble solids was low when both stages II and III were at 35/30 and high when stage I or both stages I and II were at 35/30 and subsequent growth at 18/13. Once stage III had started, temperature had little effect on berry size or total soluble solids. Acidity was highest when all stages of development were at 18/13 and was reduced by high temperature at any stage of development.
The behavior of four Saccharomyces cerevisiae strains and Torulaspora delbrueckii toward fermentation of sterile musts from Pedro Ximénez grapes in different degrees of ripeness is studied. Ethanol production by the four Saccharomyces strains was similar and higher than that of T. detbrueckii particularly in those musts of
high glucose content devoted to sherry wine making. However, the Saccháromyces strains, especially cerevisiae A and cerevisrae B, produced more volatile acidity. Regarding the aromaÚc fraction, neither cerevisiae A nor chevalieri stood out in any respect, while the remaining yeast investigated showed unlike behavior and yielded significantly different amounts of various compouñds and fractions.
Aroma compounds, as a result of their pronounced effect on the sensory organs, play a definitive role in the quality of the food and luxury products. As in the case with most food products, the aroma or "bouquet" of a wine is influenced by the action of several hundred different compounds. When dealing with wine aroma, a distinction is made among—(1) primary or grape aroma: aroma compounds as they occur in the undamaged plant cells of the grape; (2) secondary grape aroma: aroma compounds formed during the processing of the grapes (crushing, pressing, skin contact) and by chemical, enzymatic-chemical, and thermal reactions in grape must; (3) fermentation bouquet: aroma compounds formed during the alcoholic fermentation; (4) maturation bouquet: caused by chemical reactions during maturation of the wine. Numerous studies have shown that the monoterpene compounds form the axis for the sensory expression of the wine bouquet which is typical of its variety (primary or grape aroma) and that they can, therefore, be used analytically for varietal characterization. At present, more than 50 monoterpene compounds are known. Based on the quantitative determination of only 12 monoterpene substances the German white wines can be classified into three groups: "Riesling-type," "Muscat-type," and "Silvaner-WeiBburgunder-type." By including further components and by means of statistical methods, such as linear discriminant analysis, even the different varieties within the mentioned groups can be distinguished.
Comparisons were made between wines resulting from the fermentation of a single grape must of the Verdejo cultivar with various yeasts, namely the indigenous must microflora, pure cultures of Kloeckera apiculata, Torulaspora delbrueckii and Saccharomyces cerevisiae, and mixtures of these cultures, all with or without the addition of SO2. There were major differences in both volatile and non-volatile compounds. Principal component analysis and cluster analysis showed that these differences were due mainly to the effects of the sulphur dioxide upon the yeasts.
Analytical data on the wines demonstrate that the nature of a wine depends upon the particular yeasts present during the fermentation in the absence of SO2. On the other hand, if the fermentation is carried out in presence of SO2, similar wines are produced despite differences in the microflora.
The amounts of n‐propanol, iso‐butanol and iso‐amyl plus active amyl alcohol produced during fermentation of grape juice were found to vary considerably according to the yeast used. The yeasts studied included 11 wine yeasts and one brewery yeast, all belonging to the genus Saccharomyces , and 4 yeasts belonging to genera which sometimes cause wine spoilage. Experiments were carried out in the laboratory and confirmed on pilot‐plant scale.
The average production of n‐propanol in juices from 4 grape varieties varied from 13 to 106 ppm depending on the wine yeast used. The corresponding variations in the production of iso‐butanol and isoamyl plus active amyl alcohol were 9 to 37 ppm and 115 to 262 ppm respectively,. Juices from different varieties' of grapes ( Vitis vinifera ) differed somewhat in the amounts of higher alcohols formed, irrespective of the yeast strain used.
An increase in temperature of fermentation from 15° to 25° with four yeasts produced an average of 24% more iso‐amyl plus active alcohol and 39% more iso‐butanol, and 17% less n‐propanol. A yeast/temperature interaction occurred.
An increase in pH from 3.0 to 4.2 with four yeasts produced 28% more iso‐amyl plus active amyl alcohol, 85% more iso‐butanol, and 11% more n‐propanol. A yeast /pH interaction occurred.
Spoilage yeasts examined also formed higher alcohols and the amounts were not related to sugar consumed during the fermentation.
Taste thresholds of the higher alcohols, with the exception of active amyl alcohol, were measured in dry white wine with 7 tasters. Iso‐amyl alcohol thresholds ranged from 100 to 900 ppm (mean 300 ppm) and iso‐butanol and n‐propanol both exceeded 500 ppm. The average threshold of iso‐amyl alcohol in distilled water was 4 ppm. For certain tasters strains of yeast can produce sufficient differences in iso‐amyl alcohol to be detectable organoleptically, but differences in iso‐butanol and n‐propanol are not large enough to be detectable.
Improved procedures are given for the quantitative fractionation of carbonyl compounds on a column of Dowex 1 (bisulphite) and for their chromatographic examination. A new spray procedure is described for detecting SO2-binding compounds on paper chromatograms. Two wines were analysed and their calculated SO2-binding curves compared with experimentally determined values. Wine from grapes attacked by moulds and bacteria had a high SO2-binding power, due partly to dicarbonyl compounds of microbial origin, and the calculated and experimental values agreed closely. Wine from normal grapes had a lower SO2-binding power but the calculated values were slightly higher (7 to 10%) than those determined experimentally.
For a correct characterization of Madeira wine commercially available in the market, 52 samples having different types and ages, representative of the delimited region of Madeira (liquor wine of quality produced in delimited region), were analyzed in relation to physicochemical and sensorial parameters. Standard methodology for spirits and alcoholic beverages as well as a council of tasters were adopted respectively to quantify such parameters, according to European Union regulations. The main physicochemical parameters analyzed demonstrated that Madeira wine represent a high quality beverage without toxicological risks, as all constituents have in general contents clearly below the maximum concentration admissible by the national and/or international rules. A reasonable differentiation of properties could be achieved between samples having different types and ages, when principal component, discriminant and cluster analyses were applied to the analytical data, especially for physicochemical parameters.
Oxidation de l'éthanol par <i>Acetobacter rancens</i>.
- P. Dupuy
Evoluzione degli zuccheri e degli acidi nel corso della maturazione nella cv. Prosecco e suoi biotipi. (Evolution of the sugars and of the acids during the maturation for the cv. Prosecco and its biotypes.)
- A. Costacurta