Hydrolysis and formation of volatile esters in New Zealand Sauvignon blanc wine

The evolution of the varietal thiol 3-mercaptohexanol acetate (3MHA) and other key aroma compounds has been monitored in New Zealand Sauvignon blanc wines stored for 1 year at three different temperatures (5, 10 and 18 °C). The main processes that occurred in the Sauvignon blanc wines during bottle ageing were hydrolysis of 3MHA and other acetate esters, hydrolysis of ethyl esters of fatty acids, and the formation of ethyl esters of branched acids. The kinetic parameters of ester hydrolysis, including reaction rate constants and activation energies, were determined, which allow prediction of future wine composition based upon storage temperature and time. It was found that 3MHA had the highest reaction rate constant, meaning that this compound is the most unstable, particularly at higher storage temperatures, and that it disappeared very fast during wine storage.     

Influence of fruit ripeness and juice chaptalisation on the sensory properties and degree of typicality expressed by Sauvignon Blanc wines from Marlborough,New Zealand

Background and Aims: Interest in the typical sensory properties exhibited by Sauvignon Blanc wines from Marlborough, New Zealand, is increasing. Although critical from a winemaking standpoint, there is a significant lack of data concerning the extent to which these typical sensory characteristics are affected by fruit ripeness at harvest and juice chaptalisation. Methods and Results: Experimental Marlborough Sauvignon Blanc wines fermented from fruits at three different ripeness stages, with or without juice chaptalisation, were assessed by a panel of wine professionals from Marlborough. Results suggest that the balance between green and fruity ripe flavours that makes a Marlborough Sauvignon Blanc typical of its style would originate from the fruit ripeness at harvest. We also report that juice chaptalisation can modulate the wines' taste and mouthfeel properties and significantly affect their typicality as Marlborough Sauvignon Blanc. Conclusions: The production of Marlborough Sauvignon Blanc wines that well represent their specific style relies primarily on the ripeness of the fruit at harvest, the impact of which can be modulated by juice chaptalisation. Significance of the Study: This is the only study that has considered fruit ripeness and juice chaptalisation as two factors that condition the sensory properties and degree of typicality expressed by Marlborough Sauvignon Blanc wines.     

不同酵母对赤霞珠桃红葡萄酒香气的影响

利用CY3079、Zymaflore X16、TXL和STR四种不同类型的商业酵母发酵赤霞珠新鲜桃红葡萄酒,采用顶空固相微萃取（HS-SPME）结合气相色谱质谱（GC-MS）联用技术,分别对酒精发酵结束和瓶储陈酿一年的葡萄酒样品进行香气物质的定性与定量分析。结果表明,4种酵母发酵的赤霞珠桃红葡萄酒中香气物质的种类相似,但其含量差异显著。酒精发酵结束阶段,CY3079和Zymaflore X16酵母发酵的桃红葡萄酒中脂肪酸乙酯的含量高于其他酵母发酵的酒样,使它们具有更加浓郁的果香、甜香和花香;而Zymaflore X16和STR酵母产生乙酸异戊酯和乙酸苯乙酯的能力较强。经过一年的瓶储陈酿,所有处理的桃红葡萄酒中脂肪酸乙酯和高级醇乙酸酯的含量显著下降,导致其果香的强度降低,同时减少了不同酵母发酵酒样之间的差异。     

Comparative study of aromatic compounds in young red wines from cabernet sauvignon, cabernet franc, and cabernet gernischet varieties in China

ABSTRACT:  The aromatic composition and key odorants of young red wines produced from Cabernet Sauvignon, Cabernet Franc, and Cabernet Gernischet wines were compared and the reasons for the difference in their aromatic compounds were discussed. Forty-three odorants were detected in Cabernet Sauvignon and Cabernet Franc wines compared to 50 in Cabernet Gernischet wine. Quantitatively, acids formed the most abundant group in the aromatic components of the 3 wines, followed by alcohols and esters. Compared to Cabernet Sauvignon and Cabernet Franc wines, the profiles of alcohols and esters for Cabernet Gernischet wine were more diverse. Monoterpenes, namely, 4-terpinenol, citronellol, and nerol, were found solely in Cabernet Gernischet wine. Only 10 compounds, namely, ethyl octanoate, ethyl hexanoate, isoamyl acetate, ethyl butyrate, β-damascenone, ethyl decanoate, isoamyl alcohol, acetic acid, octanoic acid, and phenylethyl acetate, were always present in the 3 wines at concentrations higher than their threshold values. However, ethyl octanoate, ethyl hexanoate, and isoamyl acetate were found to jointly contribute to 97%, 98.9%, and 99% of the global aroma of Cabernet Sauvignon, Cabernet Franc, and Cabernet Gernischet wines, respectively. This result showed that the aroma indistinguishableness of the 3 wines was mainly due to the dominance of the fruity notes exerted by the ethyl esters and, to a lesser extent, to the contribution of varietal aromatic compounds to the global aroma of the wines.     

‘桂葡6号’葡萄酒花色苷组分HPLC-MS分析

利用高效液相色谱-质谱联用技术测定野生资源‘桂葡6号’乙醇发酵结束和瓶储3?个月的葡萄酒中花色苷类物质的组成及含量,并与欧亚种‘赤霞珠’进行对比。结果发现,‘桂葡6号’乙醇发酵结束和瓶储3?个月酒样中花色苷总量为548.94?g/L和427.89?g/L,分别是同期‘赤霞珠’的1.2?倍和2.7?倍左右。‘桂葡6号’乙醇发酵结束和瓶储3?个月酒样中分别检测到25?种和19?种花色苷,双糖苷是其中最主要的花色苷类型,含量最高的是甲基花青素-3,5-O-双葡萄糖苷。与欧亚种‘赤霞珠’相比,瓶储3?个月‘桂葡6号’酒样中3’,5’-羟基取代花色苷比例较高,而酰基化、甲基化和吡喃型花色苷比例较低。‘桂葡6号’花色苷组成及含量与欧亚种‘赤霞珠’差异明显,这由其品种特性决定。?     

The influence of yeast on the aroma of Sauvignon Blanc wine

The main objective of this study was to investigate the effect of different Saccharomyces cerevisiae wine yeast strains on the concentration of aroma-enhancing volatile thiols and fermentation metabolites in Sauvignon Blanc wine. Seven commercial wine yeast strains were selected based on their putative ability to modulate the concentrations of the fruity volatile thiols, 4-mercapto-4-methylpentan-2-one (4MMP), 3-mercapto-hexanol (3MH) and 3-mercapto-hexylacetate (3MHA). Each of these yeasts was used to produce Sauvignon Blanc wines under controlled conditions, in triplicate, in 20-L quantities. The levels of 4MMP, 3MH and 3MHA in these wines were quantified using the p-hydroxymercuribenzoate method. In addition, a total of 24 volatile yeast-derived fermentation aroma compounds were also quantified using headspace solid-phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME–GC–MS). Formal sensory analysis was conducted by 12 trained assessors and, additionally, a panel of 24 experienced wine industry professionals assessed the wines and ranked them in order of preference. The results indicated that the yeast strains varied significantly in terms of their capabilities to (i) produce volatile thiols and fermentation metabolites; and (ii) to modulate the varietal characters of Sauvignon Blanc wine. Yeast strains that produced the highest levels of volatile thiols were responsible for wines with the highest perceived intensity of fruitiness, and these wines were preferred by the tasting panels. While the ‘green’ characters in Sauvignon Blanc wines can be manipulated through vineyard management, the ‘tropical fruity’ characters appear to be largely dependent on the wine yeast strain used during fermentation. Therefore, the choice of yeast strain offers great potential to modulate wine aroma profiles to definable styles and predetermined consumer market specifications.     

Influence of prefermentative maceration temperature on the colour and the phenolic and volatile composition of rosé wines

Prefermentative maceration for 8 h at 5, 10 and 15 °C was used to make rosé wines, and changes in their colour (colour intensity (CI), tone and CIELAB parameters), phenolic compounds (classic indices and individual compounds) and volatile compounds (major and minor) were monitored from the must stage to wines until 6 months after bottling. The 15 °C maceration temperature provided wines with the highest CI, a* and C* values, the greatest malvidin‐3‐glucoside content and the lowest alcohol and ethyl acetate levels. Only in these wines were terpenols released after 6 months in the bottle. The wines produced at 5 °C had the highest ester levels, which also remained more stable during storage. When using maceration temperature as the differentiating variable in a discriminant analysis, volatile compounds were important contributors. However, colour and phenolic compound parameters were important when sampling time was used as the differentiating variable. The best scoring wines in an informal sensory evaluation test were those subjected to 15 °C maceration, while the least appreciated were those macerated at 5 °C. Copyright © 2005 Society of Chemical Industry     

The influence of ascorbic acid on the composition, colour and flavour properties of a Riesling and a wooded Chardonnay wine during five years' storage

This paper presents the results from an investigation to assess the development of a Riesling and a wooded Chardonnay wine over five years. The wines were bottled either with or without added ascorbic acid and stored under controlled temperature and humidity conditions. Ascorbic acid addition to wine at bottling had little effect on wine aroma and flavour when the wines in this study had been in bottle for 6 months or less. For both wines, at bottle storage times of 3 years or more, addition of ascorbic acid at bottling resulted in wines with no difference in aroma or less oxidised and/or more fresh fruity aromas, even if all the ascorbic acid had been depleted at the time of assessment, compared to wines without addition of ascorbic acid at bottling. In terms of colour, for the Chardonnay wines, the effect of ascorbic acid addition at bottling assessed between two weeks and two years after bottling suggested that wines without addition were browner and had more overall colour intensity. For the Riesling wines, ascorbic acid addition had no significant effect on brownness and overall colour intensity although the Riesling wines with ascorbic acid were generally higher in yellow colour. The A₄₂₀ measurements, which are widely used to estimate the brown colour of wines, did not always appear to correlate with the brown scores obtained by visual assessment or colour measures by CIELAB when wines with and without ascorbic acid addition were compared together. For both wines, after three and five years storage, the concentration of the antioxidant sulfur dioxide was either little different or else slightly(statistically significantly) higher in wines to which ascorbic acid was added at bottling than those without addition.     

EFFECT OF TIME AND STORAGE CONDITIONS ON MAJOR VOLATILE COMPOUNDS OF ZALEMA WHITE WINE

ABSTRACT

Changes in quality attributes during bottled storage of white wine were studied. Different storage conditions, temperature, bottle position and exposure to light were studied over 1 year and their effects on major volatile compounds were evaluated. Ethyl lactate and diethyl succinate contents increased after 12 months of storage, whereas isoamyl acetate decreased over this period. The analysis of variance revealed that the temperature had a statistically significant effect on most volatile compounds studied. Multivariate statistical techniques (specifically principal component analysis and linear discriminant analysis) confirmed that temperature is the most important factor, so the samples were distributed into two groups according to storage temperature. A rough differentiation among wines according to the length of storage was also obtained using linear discriminant analysis.

PRACTICAL APPLICATIONS

Aroma is one of the main factors contributing to the quality of wines and their acceptance by consumers. However during bottle storage, young white wines lose their fresh and fruity flavor and suffer a browning process. Among other factors, the time it takes a wine to spoil depends on the wine composition and on storage conditions. Knowledge of the bottle storage stability of Zalema young white wines could allows us to predict their shelf life and establish the best commercial storage conditions to retain their organoleptic characteristics for longer periods.     

Prediction of the storage time in bottles of Spanish white wines using multivariate statistical analysis

 Young white wines lose their characteristic fruity aroma and flavour with storage time in the bottle. The present study employed three regression methods: stepwise multiple linear regression, principal component regression, and partial least squares regression, to predict the storage times of wines in the bottle based on the composition of their volatiles. Stepwise multiple linear regression yielded the best predictions (mean error by cross validation: 0.34 years), using ten volatile compounds in the equation (diethyl succinate, butyric acid, furan derivative, N–3-(methylbutyl) acetamide, ethyl lactate, furfural, diethyl malate, ethyl caprylate, ethyl-3-hydroxybutyrate, and ethyl-4-hydroxybutyrate).     

The development of esters in filtered and unfiltered wines that have been aged in oak barrels

Esters are quite important for the aroma of aged red wine as they contribute to the fruity complex nature of this wine. This research paper measured the development of esters during maturation of Merlot red wines. These wines had different amounts of turbidity. The wine was aged for 18 months either after filtration with diatomaceous earth or without filtration. Both American and French oak barrel were used for storage. The results obtained showed that the unfiltered wine had a greater concentration of esters at the end of the storage period than the filtered wine. Fatty acid and ethanol esters decreased more than isoamyl acetate, independently of filtration. Ethyl octanoate and ethyl decanoate decreased both in filtered and unfiltered wine. Isoamyl acetate was formed in unfiltered wine and ethyl butyrate and ethyl hexanoate decreased in filtered wine while they remained constant in unfiltered wine.     

赤霞珠干红葡萄酒在不同子产区香气特征的差异

以宁夏贺兰山东麓5个不同子产区石嘴山市、银川市贺兰县、西夏区、永宁县和吴忠市红寺堡区的17款赤霞珠干红葡萄酒为研究对象,采用顶空固相微萃取与气相色谱-质谱联用法(headpace solid-phase microextraction and gas chromatography-mass spectrometry,HS-SPME-GC-MS),分析酒样的香气物质以及气味活性值(odor activity value,OAV),确定具有感官贡献的香气物质,结合主成分分析研究5个子产区之间的相关性。结果表明,酒样香气物质在组成上具有一致性,主要是醇类和酯类物质。此外,大马士酮香气贡献最为突出,使得宁夏贺兰山东麓赤霞珠干红葡萄酒香气主要具有花香和果香特征。主成分分析结果表明,利用植物香指数和脂香指数可区分不同子产区的香气特征,辛酸甲酯、乙酸苯乙酯、月桂酸乙酯;2,4-二叔丁基苯酚;苯乙醇;大马士酮和癸酸乙酯;乙酸异戊酯分别对石嘴山市、银川市贺兰县、西夏区、永宁县和吴忠市红寺堡区葡萄酒香气有重要贡献。聚类结果表明,石嘴山市和银川市西夏区葡萄酒香气更为接近。     

Low‐temperature wine‐making using yeast immobilized on pear pieces

A biocatalyst was prepared by the immobilization of Saccharomyces cerevisiae AXAZ‐1 yeast cells on pear pieces and tested for grape must fermentation in both batch and continuous conditions. The immobilized yeast cells were stable and active even at low temperatures (<10 °C). Wine production under batch fermentation at 8 °C was completed within 15 days while at 3 °C it took 36 days. In continuous fermentation, the bioreactor was operated for 33 days, then stored for 12 days at 10 °C, and re‐run for another 15 days without any diminution of the ethanol productivity. Total acidity of the produced wines remained within the ranges usually observed in dry wines, while volatile acidity was found in rather increased levels. The concentrations of higher alcohols (1‐propanol, isobutyl alcohol and amyl alcohols) were relatively low, while ethyl acetate was detected at up to 118 mg l^?1, contributing to the fruity aroma of the wines produced. Preliminary sensory evaluations carried out in the laboratory indicated the fine quality of the produced wines. Copyright © 2004 Society of Chemical Industry     

烟台产区三个葡萄品种原白兰地香气成分及感官特征的对比

以烟台产区三种酿酒葡萄白玉霓（Ugni Blanc）、蛇龙珠（Cabernet Gernischt）和赤霞珠（Cabernet Sauvignon）为原料酿造葡萄原白兰地,并对其中挥发性香气成分及其感官特征进行分析。结果表明,三个品种葡萄原白兰地共检测到64种挥发性香气成分;其中白玉霓原白兰地的酯类物质种类最丰富,但含量差异不显著（P＞0.05）;蛇龙珠原白兰地的醇类、酸类、醛酮类及缩醛类物质总含量最高且差异显著（P＜0.05）;赤霞珠原白兰地的芳香类、萜烯类和降异戊二烯类物质总含量最高且差异显著（P＜0.05）;丁酸乙酯等26种化合物可很好实现对三个品种原白兰地的判别分类,蛇龙珠与白玉霓品种间聚类距离更近。三个葡萄品种均符合原白兰地的原料质量要求,感官质量综合排序为白玉霓＞蛇龙珠＞赤霞珠。     

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).