To investigate the varietal aroma compound composition of monovarietal grape marc distillates made from six different varieties (Vitis vinifera L.) in the region of Istria (Croatia), 30 samples were ...subjected to GC/MS and GC/FID analysis. A total of 73 compounds were identified: 45 monoterpenes, 20 sesquiterpenes, 3 diterpenes, and 5 C13-norisoprenoids. The largest number and the highest concentration of monoterpenes were found in Muscat Blanc, followed by Rose Muscat of Poreč (Muškat ruža porečki) distillates, which were both characterized as highly aromatic. Lower, but still significant monoterpenol content was determined in distillates made from Istrian Malvasia (Malvazija istarska) grape marc. Chardonnay, Cabernet Sauvignon, and Teran distillates exhibited poorer monoterpene profiles, while Teran distillates contained elevated sesquiterpene concentrations. It was concluded that investigated monovarietal grape marc distillates significantly differ in varietal aroma compound composition. Stepwise linear discriminant analysis provided efficient discrimination models, and extracted various monoterpenes, sesquiterpenes and C13-norisoprenoids as important differentiators of distillates according to varietal origin.
The determination of the grape variety of aged red wines based on the ratio of acetylated and coumaroylated anthocyanins (
R
ac/coum) can be influenced by the formation of pyranoanthocyanins. ...Coelution of the pyranoanthocyanin pinotin A and the 3-coumaroylglucoside of malvidin can affect the obtained data for the
R
ac/coum values, which in turn could lead to a false classification of wine variety and rejection of the wines by the food authorities. Investigations using different reversed phase high performance liquid chromatography columns demonstrate the importance of a good chromatographic resolution of these analytes.
Wine colour, phenolics and volatile fermentation-derived composition are the quintessential elements of a red wine. Many viticultural and winemaking factors contribute to wine aroma and colour with ...choice of yeast strain being a crucial factor. Besides the traditional
Saccharomyces
species
S. cerevisiae
,
S. bayanus
and several
Saccharomyces
interspecific hybrids are able to ferment grape juice to completion. This study examined the diversity in chemical composition, including phenolics and fermentation-derived volatile compounds, of an Australian Cabernet Sauvignon due to the use of different
Saccharomyces
strains. Eleven commercially available
Saccharomyces
strains were used in this study;
S. cerevisiae
(7),
S. bayanus
(2) and interspecific
Saccharomyces
hybrids (2). The eleven Cabernet Sauvignon wines varied greatly in their chemical composition. Nine yeast strains completed alcoholic fermentation in 19 days;
S. bayanus
AWRI 1375 in 26 days, and
S. cerevisiae
AWRI 1554 required 32 days. Ethanol concentrations varied in the final wines (12.7–14.2 %). The two
S. bayanus
strains produced the most distinct wines, with the ability to metabolise malic acid, generate high glycerol concentrations and distinctive phenolic composition.
Saccharomyces
hybrid AWRI 1501 and
S. cerevisiae
AWRI 1554 and AWRI 1493 also generated distinctive wines. This work demonstrates that the style of a Cabernet Sauvignon can be clearly modulated by choice of commercially available wine yeast.
Three flavor-active volatile thiols (4-mercapto-4-methylpentan-2-one, 4-mercapto 4-methylpentan-2-ol and 3-mercaptohexan-1-ol) involved in Vitis vinifera L. var. Sauvignon blanc wine aroma can be ...generated in vitro from nonvolatile must extracts by the enzyme action of a cell-free extract obtained from the gastrointestinal bacterium Eubacterium limosum. The specificity of a cysteine conjugate beta-lyase (EC 4.4.1.13) which is contained in the cell-free extract, strongly suggested the existence of precursor for these volatile thiols having a structure of S-cysteine conjugate. Gas-phase chromatography analysis coupled with mass spectrometry of must extract in the form of trimethylsilylated derivatives, verified this hypothesis. The release of flavor-active volatile thiols during alcoholic fermentation of the must is shown to be due to the degradation, by yeast, of the corresponding S-cysteine conjugates. This mechanism explains the amplification of the typical Sauvignon blanc grape aroma during alcoholic fermentation.
The legal recognition of the geographical origin of wines, named Appellation of Origin, is of great interest for both consumers and producers, since it provides decisive criteria of acceptability in ...terms of guaranteed quality. However, when wines are considered to differ among the viticultural regions where they are produced, it is difficult to verify if the distinction is actually linked to their provenance, or, conversely if it is merely due to the work of the winemaker. Therefore, there is a need for methods that separate the effect of the geographical location from that of the human factor. Thirteen Merlot and 14 Cabernet Sauvignon vineyards were selected from two Appellations of Origin, named Binissalem and Pla i Llevant, located in the Balearic Islands (Spain). Grapes and soils were sampled evenly over the whole surface of each vineyard. Climatic and landscape conditions were also registered at each site. Univariable analysis was performed to evaluate the effect of the Appellation of Origin on the color intensity, the color tonality and the phenolic content of grapes, the silts, sands, clays and carbonate content of soils, the rainfall, the maximum and minimum temperature, and the elevation of the vineyards in 2009 and 2010. Based on the soil, climate, and landscape characteristics, a Partial Least Square Discriminant Analysis was used to discriminate between both Appellations of Origin. Results showed that a particular agroclimatic terroir may be defined for each Appellation of Origin. Indeed, this multivariate analysis led to a correct classification rate of 95 % for both 2009 and 2010 models and a prediction accuracy higher than 85.7 %. The research here proposed a methodology suitable for evaluating the appropriateness of contiguous viticultural Appellations of Origin in terms of a whole terroir concept, without considering the human factor.
Aims: Identification and characterisation of terroirs depends on knowledge of environmental parameters, functioning of the grapevine and characteristics of the final product. Field studies, resulting ...in point data, are necessary to investigate the functioning of the grapevine but in order for this information to be of use within zoning studies it must be placed in a spatial context. Methods and results: A knowledge-driven model used the rules generated in regression tree analyses to directly classify natural terroir units with respect to expected response of Cabernet-Sauvignon and Sauvignon blanc in the Stellenbosch Wine of Origin District. The natural terroir units were then grouped into terroir units that were homogenous with respect to predicted response of selected viticultural and oenological variables for each studied cultivar. Conclusions: The use of regression tree methodology (CART analyses) enabled the definition of decision trees for spatialisation of this data. Each natural terroir unit could be evaluated with respect to its potential viticultural and oenological response and thus grouped to identify terroir units. Significance and impact of the study: The identified terroir units can only be considered preliminary but the methodology used has promising implications for different scales of study.
To study the effects of different drip irrigation modes on the wine grape root distribution is the basis of formulating fertilization, irrigation, and over-wintering management practices for wine ...grape. Taking the wine grape "Cabernet Sauvignon" as test material, this paper studied the effects of different water-saving irrigation modes (drip irrigation under straw mulching, drip irrigation under plastic mulching, double-tube drip irrigation, and single-tube drip irrigation) on the root distribution of wine grape in the desert area of Northwest China, with the conventional furrow irrigation as the control. The root system of the "Cabernet Sauvignon" was distributed from 0 to 70 cm vertically, and from 0 to 120 cm horizontally. With double-tube drip irrigation, the root amount was the largest (138.3 roots per unit profile), but the root vertical distribution scope was narrowed by 20 cm, as compared to the control. Drip irrigation with straw mulching increased the root amount significantly, and increased the roo
Chemical composition of white wine Sauvignon blanc var. was assessed during storage from January until August. Common analytical methods were applied for alcohol content, total reducing sugar, ...sulphur dioxide and total acidity analysis. The value for total reducing sugar of 1,8 g/L, could include the Suvignon blanc wine as dry wine. There was observed a loss in alcohol content with 5% in the stored white wine. In order to ensurre the wine stabilization, the amount of sulphur dioxide increased gradually from cold to warm season, in August reaching the highest value of 130 mg/L total SO2.
Co-winemaked Monastrell wines with Cabernet Sauvignon or Merlot, at different proportions have been studied for first time in terms of its odor activity value (OAV) in young wines, aging wines (after ...9 months in French oak barrels) and bottled aging wines (aging wines after 6 months in the bottle). The co-winemaking wines showed a different aromatic complexity as they were fruitier and sweeter than the monovarietal ones, enhancing their aroma characteristics, being more evident at 60:40 proportion in case of Merlot for young and aging wines and Cabernet Sauvignon for bottled ones. In terms of extractable oak compounds, Monastrell-Merlot wines showed the highest values suggesting that they may need a shorter period within the barrel than Monastrell-Cabernet Sauvignon ones.
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