Chemometric investigation of the volatile content of young South African wines

The content of major volatiles of 334 wines of six different cultivars (Sauvignon Blanc, Chardonnay, Pinotage, Shiraz, Cabernet Sauvignon and Merlot) and vintage 2005 was used to investigate the aroma content of young South African wines. Wines were sourced from six different regions and various producers. Thirty-nine volatile components partially responsible for the flavour of wine were quantified. In order to investigate possible correlation between volatile content and grape variety and/or geographical origin, analysis of variance, factor analysis (FA), principal component analysis (PCA) and linear discriminant analysis (LDA) were used. Significant differences in the levels of certain volatiles were observed as a function of region and cultivar, with the latter factor proving to be more influential. A few volatile compounds were identified as potential predictors of the white wine cultivars. Prediction for red wine cultivars was poor, with the exception of Pinotage wines, for which three compounds (isoamyl acetate, isoamyl alcohol and ethyl octanoate) were identified as accurate predictors. The reasons for the importance of these three volatile compounds in distinguishing young Pinotage wines are discussed, and possible reasons for the unique levels in wines of this cultivar are highlighted.     

盐碱荒漠化戈壁酿酒葡萄的果实品质比较分析

为分析10个酿酒葡萄品种和种植年份的成熟期葡萄的主要理化品质,以嘉峪关紫轩葡萄园区红葡萄品种（山葡萄、梅鹿辄、左优红、北冰红、赤霞珠）和白葡萄品种（霞多丽、威代尔、贵人香、白玉霓）为原料,分析比较不同品种葡萄的单粒质量、果粒径、总可溶性固形物、总糖、总酸、糖酸比、总酚及单宁含量。不同品种葡萄中不同物质的含量存在差异,红葡萄品种梅鹿辄、赤霞珠和白葡萄品种威代尔、贵人香4个品种的糖酸比、总酚含量和单宁含量比较高,品质较好,适宜于嘉峪关紫轩葡萄园区的栽培环境。     

Chemometric and phenolic attributes of blended wines assessed by multivariate techniques

The aim of the study was to investigate the quality of blended wines produced from Vitis vinifera L. Cabernet Sauvignon, Merlot and Sauvignon blanc grapes. Wines were processed according to accepted conventional methods for white and red wines. Blended wines were produced with different ranges (25, 50, 75 and 100%) of Cabernet Sauvignon, Merlot and Sauvignon blanc wines. Produced wines were evaluated for total phenols (mg/L), total tartaric esters (mg/L caffeic acid), total flavonols (mg/L quercetin), chemometric parameters such as D280%, D420%, D520%, D620%, dA%, CD%, T, CI%, R%, Y% and B%, CIELAB parameters, protein, total and volatile acidity. Analyses on an n‐dimensional scale demonstrated the relationships among the wines of different grape origins and different blending ratios. On the basis of these differences, two main groups were plotted using principal component analysis and cluster analysis. The results demonstrate the possibilities of optimizing wines on the basis of defined parameters. Copyright © 2015 The Institute of Brewing & Distilling     

The role of olfaction in the elaboration and use of the Chardonnay wine concept

The existence of a Chardonnay wine concept was explored in two experiments. In the first experiment, 28 Chardonnay wine experts assessed in terms of a score the degree of representativeness of 48 white wines according to their own Chardonnay wine concept. The samples were 29 wines made from Chardonnay grapes and 19 wines made from other grape varieties (Aligoté, Melon de Bourgogne, Sylvaner, Sauvignon blanc, Chenin, Marsanne and Pinot blanc). Two assessment conditions were conducted: orthonasal and global (orthonasal plus retronasal and mouthfeel perceptions). Globally, scores were higher for Chardonnay wines than for non-Chardonnay ones and the consensus among experts demonstrated the existence of a shared Chardonnay wine sensory concept. The global evaluation led to a better discrimination between Chardonnay and non-Chardonnay wines, indicating that the sensory concept includes olfactive as well as taste and mouthfeel sensations. In the second experiment, the perceptive similarities of a subset of 18 wines (nine among the less representative and nine among the most representative) were studied. Twenty consumers freely sorted the wines according to odour similarity. Results were analysed by means of multidimensional scaling. Except for an extreme wine exhibiting very low representativeness, no clear separation of wines according to a Chardonnay wine concept was observed on the MDS space. However, a regression analysis showed significant correlations between representativeness scores and the first and third dimensions of the MDS space. This suggests that the Chardonnay wine concept is an experts' construct, elaborated by specific weighing of sensory features, partially based on perceptive similarities.     

葡萄籽油中植物甾醇的提取与鉴定

以4种酿酒葡萄(美乐、赤霞珠、龙眼、霞多丽)的种籽为原料,提取葡萄籽油,经皂化、萃取制得植物甾醇。采用GC-MS方法首次分析了葡萄籽油中植物甾醇的组成及含量,结果从葡萄籽油中检测到6种植物甾醇(菜油甾醇、豆甾醇、β-谷甾醇、岩藻甾醇、豆甾烷醇、环木菠萝烯醇),其中白葡萄品种(龙眼、霞多丽)籽油中总甾醇含量高于红葡萄品种(龙眼、霞多丽)。在鉴定出的6种植物甾醇中,β-谷甾醇含量最高,其次是豆甾醇和菜油甾醇,岩藻甾醇含量最低。     

Volatile Composition of Macedonian and Hungarian Wines Assessed by GC/MS

The volatile composition of eight varietal wines Vranec, Merlot, Cabernet Sauvignon, Temjanika and Chardonnay from the Republic of Macedonia, and Portugieser, Kékfrankos and Tokaji Aszú from Hungary has been characterized by means of gas chromatography/mass spectrometry technique. The wine volatile compounds were extracted in dichloromethane, and the extracts were concentrated under nitrogen. Forty-four volatile compounds have been identified mainly using the NIST mass spectral library and by comparison with the available standards used for quantification as well. Differences between the wines were noted for a number of compounds, such as a higher concentration of 1-pentanol and 2-phenyl ethanol in the red wines. Monoterpenes, linalool and terpineol were detected only in the white wines, Chardonnay and Tokaji. Macedonian red wines were characterized by a higher level of alcohols, while the Hungarian wines contained a higher amount of esters, fatty acids and lactones. A statistical treatment including one-way ANOVA, followed by a Tukey’s test has been performed in order to ascertain possible significant differences between the wines studied, and principal component analysis to study the possible grouping of the wines.     

Antioxidant capacity and stilbene contents of wines produced in the Snake River Valley of Idaho

Forty-two wines produced from grapes grown in Idaho were examined in this study. The samples examined were from four monovarietal wines (12 Cabernet Sauvignon, 9 Merlot, 7 Riesling, 14 Chardonnay). Wine samples represented twelve wineries that obtain their fruit from vineyards located within Idaho’s Snake River Valley. Titratable acidity, pH, specific gravity, colour measurements (lightness, chroma, and hue), % haze, total anthocyanins, total phenolics, total tannins, antioxidant capacity, and individual stilbene measurements were performed. The antioxidant capacities (ORAC values) of Idaho wines ranged from 3.1 (Merlot wine) to 87.0 (Cabernet Sauvignon wine) μmol of Trolox/ml (mean = 38.5 μmol of Trolox/ml). Mean ORAC values of Merlot wines (mean = 27.6 μmol of Trolox/ml) were lower than the other three styles (mean for Cabernet Sauvignon wines = 41.0 μmol of Trolox/ml, mean for Chardonnay wines = 42.8 μmol of Trolox/ml, and mean for Riesling wines = 39.4 μmol of Trolox/ml). Free stilbene levels (four different stilbenes) were examined by direct-HPLC/DAD/ESI-MS/MS method. Piceid and resveratrol (both trans- and cis-) were found in the samples. Stilbene levels ranged from 0.97 (Riesling wine) to 12.88 (Cabernet Sauvignon wine) mg (expressed as trans-resveratrol)/l. This is the first paper to report the current chemical composition of Idaho wines.     

Is buttery aroma perception in wines predictable from the diacetyl concentration?

An important flavour compound associated with malolactic fermentation (MLF) is the volatile di-ketone, diacetyl (2,3-butanedione), which is considered as the major contributor to buttery flavour in wines. Commercial Chardonnay, Cabernet Sauvignon, Merlot and Shiraz wines from eight vintages (1992–1999), 20 viticultural regions and 28 wine producers were analysed for diacetyl and also the buttery aroma intensity was rated by a trained sensory panel. The wines examined were found to have a wide range of diacetyl concentration, i.e. 0.3 to 0.6 mg/L (mean value 0.4 mg/L) for the 24 Chardonnay wines, and 0.3 to 2.5 mg/L (mean value 1.1 mg/L) for the 43 red wines. The buttery aroma, while significantly correlated with diacetyl concentration in the Chardonnay wines ( P < 0.01), was not predicted very well by the regression equation, but the prediction was improved when the free sulfur dioxide concentration of the wines was taken into account (adjusted R²= 0.43, P < 0.01). There was a weak, although statistically significant, correlation between diacetyl concentration and the buttery rating for the red wine data set, when the sulfur dioxide concentration was taken into account (adjusted R²= 0.12, P < 0.05). This weak correlation may have been, in part, due to the generally low concentration of diacetyl in relation to the published aroma threshold in red wine. It was also noted that there was a substantial decrease in diacetyl concentration for a subset of red wines, but not for white wines, of various vintages cellared for three years at 15C.     

Varietal discrimination of Chilean wines by direct injection mass spectrometry analysis combined with multivariate statistics

A simple, direct injection, electrospray ionization Fourier transform mass spectrometry (ESI FT-MS) method, in combination with multivariate statistics, was used for the characterization and sorting of Chilean wines. 47 commercial red wines labelled as Cabernet Sauvignon, Carménère, Syrah, and Pinot noir, and 25 white wines of the varieties Chardonnay and Sauvignon blanc were diluted, directly infused into the mass spectrometer, and analyzed in negative ion mode. The signature ions used for statistical analyses were manually filtered out from the signals with m/z ratios over 10%. The results of principal component analysis allowed a good sorting of white wines, but not so in the case of reds. The main three principal components explained 96.82% and 85.65% of the variance for white and red wines, respectively. Instead, linear discriminant analysis, allowed the correct discrimination of 100.00% of white and 95.74% of red samples. The validation of these results using the leave-one-out cross-validation method gave lower percentages of correct classification (76.00% and 61.70% of white and red samples respectively), suggesting that some of the wine samples analyzed might have been blends of more than one variety. Consequently, ESI FT-MS direct injection analysis of wines can be used for sample discrimination, but requires a stronger mathematical model built with spectral information of pure and blended samples before improving the percentages of classification.     

海拔对美乐和赤霞珠葡萄酒中酚类物质含量、抗氧化活性及酯类香气成分的影响

为研究海拔对大渡河干旱河谷地区美乐和赤霞珠葡萄酒的影响,以该地区海拔2280、2390 m葡萄园种植的美乐和海拔2280、2390、2600 m葡萄园种植的赤霞珠果实所分别酿造的干红葡萄酒为研究对象,对其理化指标、酯类香气物质含量、抗氧化活力及感官特征进行分析。结果表明:随海拔上升,2种(美乐和赤霞珠)葡萄酒的残糖含量降低,总酸、干浸出物、总酚、单宁、总类黄酮、总花色苷含量、色度、DPPH清除力以及铜离子还原力增加;2种葡萄酒酯类物质的相对含量随海拔上升呈下降趋势,但海拔对2种葡萄酒主要酒酯类香气的构成无影响,通过主成分分析,将葡萄酒酒样的酯类成分提取为3个主成分,累计贡献率达93.021%;葡萄酒感官得分随海拔升高而升高,但海拔过高对葡萄酒感官质量有负作用,海拔2390 m赤霞珠葡萄酒感官质量最佳;通径分析表明,总酚对葡萄酒感官质量有直接的重要作用。     

Evaluating the value of replicate tastings of a given wine: bio-statistical considerations

Wine judges were randomly selected from the membership of the American Association of Wine Economists (AAWE) to participate in a blind triplicate tasting of two South African varietals: one Sauvignon Blanc and one Pinotage; as well as a blind tasting of a single pouring of five additional Sauvignon Blanc wines and five additional Pinotage wines. It was hypothesized that those wine Tasters who scored the triplicate wines reliably would also score the single poured wines reliably; and, conversely, those who were unreliable on the triplicate wines would also be unreliable on the additional five wines. The results were substantially confirmative for the Sauvignon varietals, but only minimally confirmative for the Pinotage varietals. Two possible reasons are, first, the simpler structure of Sauvignon Blanc (a white wine) and possible palate fatigue for the more complex Pinotage (a red wine).     

三种不同珠干红葡萄酒品质的对比性研究

选取烟台地区的赤霞珠、梅鹿辄和蛇龙珠葡萄为原料,采用相同的工艺酿造干红葡萄酒,对酒的品质进行对比研究。结果表明,酒中3-甲基-1-丁醇、2-甲基-1-丁醇、1-己醇、β-苯乙醇、4-羟基-苯乙醇、甘油、丁二酸单乙酯、1,4丁内酯和丁二酸二乙酯的含量为赤霞珠＞梅鹿辄＞蛇龙珠。赤霞珠、梅鹿辄葡萄酒中2-甲基-1-丙醇的含量均高于蛇龙珠葡萄酒。蛇龙珠葡萄酒中丙醇、1-丁醇、丁二醇的含量较高。蛇龙珠葡萄酒中乳酸含量最高,而梅鹿辄葡萄酒中酒石酸含量最高。梅鹿辄、赤霞珠葡萄酒中杨梅素、槲皮素含量分别为蛇龙珠葡萄酒的5.0倍、6.4倍和19.6倍、44.5倍。蛇龙珠葡萄酒中除对香豆酸外,其余酚类物质的含量较少。梅鹿辄和赤霞珠葡萄酒的感官得分高于蛇龙珠葡萄酒。     

Varietal and geographic classification of French red wines in terms of pigments and flavonoid compounds

Thirty-four French red wines originating from six different grape varieties and three different production areas were analysed in duplicate for 15 anthocyanins, ten flavonoids and three colour parameters, F-statistics, principal component analysis and stepwise discriminant analysis were used to identify and to explain differences among samples. Clear difference between wines made from different varieties were mainly related to anthocyanin 3-acylglucosides. Malvidin and peonidin 3-acetylglucosides were found in increasing concentrations in wines made respectively from Grenache, Carignan, Cinsault, Merlot, Carbernet Sauvignon and Cabernet Franc grapes; the concentrations of peonidin and malvidin 3-p-coumarylglucosides were higher in the Cinsault wines studied. Cabernet Sauvignon and Merlot wines made near Bordeaux had a less intense colour and a higher malvidin 3-glucoside content than wines from the same varieties produced near Narbonne. Wines made from Merlot, Cabernet Sauvignon and Cabernet Franc grapes contained more catechin, epicatechin and myricetin when produced in the south than in the north (Narbonne, Bordeaux, Angers). Of the samples analysed, 96%, and all of the nine extra wines, were correctly classified according to the variety of the grapes using four anthocyanins and catechin selected by step wise discriminant analyses.     

Differentiation of co-winemaking wines by their aroma composition

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.     

不同酒帽管理方式对干红葡萄酒理化指标和感官质量的影响

以赤霞珠、梅洛为原料制备干红葡萄酒,探究带皮发酵期间压帽法和浸入法两种不同的酒帽管理方式对葡萄酒发酵和其基础理化指标、感官质量的影响。结果表明,采用压帽法、浸入法的组别发酵速率存在差异,发酵终产物总酚含量分别为641.17～836.17 g/L、722.00～883.67 g/L,总花色苷含量分别为130.98～210.70 g/L、172.72～259.45 g/L,b*值（黄化程度）分别为27.52～35.78、35.23～36.77。对于梅洛葡萄酒,浸入法在发酵中后期对提升酒中总酚、总花色苷含量方面发挥重要作用,但这一优势在赤霞珠葡萄浸渍过程中并不明显。感官评价结果表明,浸入法可显著提升赤霞珠葡萄酒口感复杂度和梅洛葡萄酒余味持久度。     

葡萄酒优良红葡萄酒品种简介

介绍了赤霞珠、品丽珠、蛇龙珠、梅尔诺、黑比诺、色拉、佳美、增芳德、晚红蜜、宝石、法国蓝、桑娇维赛、歌海娜等二十二个红色酿酒品种的特性。     

Changes of Phenolic Acids During Aging of Organic Wines

Grapes (Vitis vinifera L. origin var: Carignane, Cabernet Sauvignon, Merlot, Grenache, Columbard, and Semillon) were cultivated and processed according to accepted organic agriculture and organic wine techniques. Aged wines (5 years) were evaluated for changes of their phenolic acids. The highest reduction of gallic acid concentrations were determined in Cabernet Sauvignon (24.36 mg/L) and Carignane (16.00 mg/L) wines. The quantities of p-hydroxybenzoic acid decreased mostly in Carignane (22.47 mg/L) and Columbard (20.84 mg/L) wines. The decreases of syringic acid were dominant in Cabernet Sauvignon (2.34 mg/L) and Carignane (1.69 mg/L) wines. In the case of ferulic acid, the highest reduction was determined in Cabernet Sauvignon (3.97 mg/L) wines. The decreases of p-coumaric acid contents were the same and mostly in Merlot (1.06 mg/L) and Grenache (1.035 mg/L) wines. The principal component analyses results demonstrated the relations among aged wines produced from different grape varieties and their phenolic acids. The distribution of data was accumulated into two groups. The first group included total phenols, gallic acid, p-hydroxybenzoic acid, syringic acid, p-coumaric acid, and Merlot/Carignane/Grenache wines. The second one included ferulic acid and Cabernet Sauvignon wine.     

Differentiation of wines according to grape variety using multivariate analysis of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection data

Headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry detection (GC×GC/TOFMS) was used to analyse the volatiles in five types of wines elaborated with grapes of Cabernet Sauvignon, Merlot, Chardonnay, Sauvignon Blanc and Pinot Noir varieties. Fisher ratio, principal component analysis (PCA) and stepwise linear discriminant analysis (SLDA) were used to develop a discriminant model and, as a result, 12 volatile compounds enabled differentiation and classification of wines according to grape cultivars. A detailed examination of GC×GC/TOFMS data showed that the use of one-dimensional gas chromatography with a mass spectrometric detector (1D-GC/MS) would probably result in misidentification of some of these 12 compounds, as they showed partial coelution with other components in the first chromatographic dimension.