Concentration of volatile compounds in Chardonnay wine fermented in stainless steel tanks and oak barrels

The influence of the type of container used in alcoholic fermentation on the formation of volatile compounds in wine from Chardonnay variety was studied. To do so, must from Chardonnay variety was fermented in both stainless steel tanks and in new Nevers oak barrels. The results obtained showed that wine fermented in barrels had a greater concentration of higher alcohols and esters than wine fermented in tanks. Concentration of isoamyl acetate, ethyl hexanoate, ethyl octanoate and ethyl decanoate was four times higher in wine fermented in oak barrels than in wine fermented in stainless steel tanks. With regard to the concentration of acids, a greater concentration of medium-chain fatty acids (C6:0–C10:0) was noticeable in wine fermented in oak barrels. Given that these acids are toxic for the yeasts, they may be responsible for the slower fermentation rate of wine fermented in oak barrels.     

橡木桶陈酿对红葡萄酒抗氧化性的影响

采用2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸（ABTS）方法动态监测经橡木桶陈酿和未经橡木桶陈酿的红葡萄酒的反应过程,比较在测定其抗氧化活性的反应条件上的差异,从而确定适合检测的最佳反应条件,并分析橡木桶陈酿对红葡萄酒中酚类物质含量和抗氧化活性的影响。结果表明,ABTS方法测定经橡木桶陈酿的红葡萄酒抗氧化活性的最佳反应时间范围是240～280 min,最佳稀释比例范围为1∶100～2∶100,未经橡木桶陈酿的最佳反应时间范围是220～260 min,最佳稀释比例范围是3∶100～4∶100,此条件下各因素与自由基清除率的线性关系R2均＞0.999。试验证明,采用合适的检测方法测定不同陈酿方式酒的抗氧化活性有利于提高检测效率和准确性,经橡木桶陈酿过的红葡萄酒中的酚类物质含量和抗氧化活性更高。     

Physicochemical and sensory evaluation of wine brandies aged using oak and chestnut wood simultaneously in wooden barrels and in stainless steel tanks with staves

This study provides innovative information on the simultaneous use of Limousin oak and chestnut wood in the ageing of wine brandy. Ageing was performed in 650‐L wooden barrels and in 3000‐L stainless steel tanks with staves over a 2‐year period. Effect of both kinds of wood in the brandy features depended on the ageing technology. Stainless steel tanks with staves originated lower enrichment of the brandy in dry extract (0.89 vs. 1.25 g L^?1), total phenolics (22.33 vs. 29.40) and low molecular weight extractable compounds (119.83 vs. 231.65 mg L^?1), but promoted a faster evolution of the analytical colour (lower L*, higher C*, a* and b*) and sensory colour (topaz and greenish vs. golden). The aroma and flavour profiles of the brandy were not significantly influenced by the ageing technology. Therefore, it is a promising option for both ageing technologies because it ensures the quality of brandy, together with a lower cost of the wood and exemption of the blending operation.     

不同类型国产橡木制品对葡萄酒陈酿香气的影响

采用顶空固相微萃取与气相色谱-质谱联用技术,检测蒙古栎制成的橡木片和橡木板陈酿的葡萄酒中主要陈酿香气成分的变化。结果表明:在90 d的陈酿过程中,糠醛和5-甲基糠醛含量在陈酿10至20 d即可达到最高值,此后其含量快速减少;愈创木酚和甲基愈创木酚含量则在陈酿20 d达到最高值以后,基本保持不变;顺式和反式橡木内酯含量在整个陈酿过程中一直呈增加趋势;而香草醛含量在采用橡木片和橡木板陈酿的葡萄酒中,具有不同的变化趋势:橡木片陈酿的葡萄酒,香草醛含量在30d时即达到最高值,此后逐渐减少,而橡木板陈酿的葡萄酒,香草醛含量在90 d的陈酿过程中一直增加;乙基愈创木酚和乙基苯酚含量仅在陈酿30和60 d后才显著增加。橡木片和橡木板陈酿的葡萄酒之间,除乙基苯酚和乙基愈创木酚含量无显著差异外,糠醛、香草醛、愈创木酚和橡木内酯的含量均具有显著差异,表明橡木制品的类型对葡萄酒的陈酿香气具有重要影响。      

Accumulation of volatile oak compounds in a model wine stored in American and Limousin oak barrels

Changes in concentration of oak-derived volatile compounds extracted into a model wine stored in four American and four Limousin oak barrels were measured over a 93-week period. The accumulation curves for cis- and trans-oak lactone and eugenol were asymptotic and virtually identical in shape. Guaiacol was extracted more rapidly in the first six weeks, and then continued to accumulate in a near-linear fashion. 4-Methylguaiacol and maltol did not increase significantly in concentration beyond the first year of storage. The accumulation curve for vanillin was asymptotic during the first 32 weeks and linear thereafter, indicating more than one mechanism for generating this compound in oak. The extraction curve for cyclotene was linear throughout the maturation period and was consistent with a generation by slow acid hydrolysis of precursors formed during coopering.     

The effect of successive uses of oak barrels on the extraction of oak-related volatile compounds from wine

Changes in the concentration of furfuryl compounds, guaiacol and 4‐methylguaiacol, cis‐ and trans‐oak lactone, and vanillin were studied during the maturation of wines in oak barrels of different origins (French oak and American oak). The rate at which these volatile compounds accumulated in the wines followed a curve that fits to mathematical models. The changes in concentration were usually consistent with diffusion kinetics. When the barrels are new, the concentration gradient between the wood surface and the wine is high, so diffusion occurs quickly, especially in the case of lactones, the extraction rate of which could be fitted to a power curve. After some time of maturation, the concentration gradient is not so large and furthermore, the wood surface may be exhausted of some compounds so the rate of extraction decreases. During the second fill, the rate of accumulation of these compounds in the wine was almost linear, especially during the first 6 months of storage, and the quantities measured in wine were much lower. The concentration of some compounds, increased during the final 3 months (between days 180 and 270), exhibiting a quadratic curve when plotted. Furfuryl aldehydes behaved differently as they are extracted very rapidly from the first millimetres of wood surface and transformed into furfuryl alcohol, a compound with no organoleptic significance.     

橡木片对笃斯越橘果酒颜色和酚类物质含量的影响

采用分光光度法和CIELab法,检测不同浓度橡木片陈酿的笃斯越橘果酒酚类物质含量和颜色参数的变化。结果表明:添加橡木片的笃斯越橘果酒,其总酚和总花色苷含量在不同陈酿阶段均显著提高,总类黄酮含量在陈酿1个月和3个月时显著高于不添加组,陈酿6个月后无显著性差异;橡木片能够提高辅色类花色苷的比率,降低聚合类花色苷比率;相对于不添加组,橡木片陈酿的笃斯越橘果酒在各陈酿阶段L*值、b*和H*值均显著降低,a*值显著上升。添加2 g/L和4 g/L橡木片之间,陈酿1个月和3个月各项指标均具有显著性差异,陈酿6个月,差异性不显著。研究表明橡木片对笃斯越橘果酒酚类物质含量和颜色具有重要影响且添加量为4 g/L时效果更明显。      

橡木桶陈酿对红葡萄酒中白藜芦醇含量的影响

研究了不同产地橡木材质、不同容积的橡木桶对梅鹿辄干红葡萄酒进行陈酿处理后干红葡萄酒中白藜芦醇含量的影响。试验结果表明,使用法国卢浮橡材质橡木桶陈酿的干红葡萄酒比美国白栎材质橡木桶的白黎芦醇含量高0．06mg／L;使用225L橡木桶陈酿的干红葡萄酒比300L的橡木桶的白黎芦醇含量高0．03mg/L。     

气质联用测定分析橡木片对蓝莓果酒香气的影响

利用顶空固相微萃取（SPME）结合气相色谱-质谱联用（GC-MS）技术分析橡木片的添加对蓝莓果酒中主要香气物质的影响。结果表明：通过GC-MS检测两种果酒,未添加橡木片的蓝莓果酒中共检测到26种挥发性物质,其中醇类3种,酯类17种,其他6种（包括醛类、酸类、酮类）;而添加了橡木片的蓝莓果酒共检测到29种挥发性物质,其中醇类4种,酯类18种,其他7种（包括醛类、酸类、酮类）。结果表明,添加橡木片的蓝莓果酒获得了更多的香气物质如辛酸乙酯、顺-1,3-二甲基环戊烷、3-甲基丁酸乙酯等,使得添加橡木片的蓝莓果酒香气也更加浓郁,提高了蓝莓果酒的品质。     

Use of microfungi in the treatment of oak chips: possible effects on wine

BACKGROUND: Oak barrels are commonly used in the aging of wines and spirits because of their positive effects on the product. In recent years the addition of oak chips has been used to introduce desirable wood aromas and flavours into wines. In this study, oak chips in saline solution or laboratory medium were inoculated with Penicillium purpurogenum, Aureobasidium pullulans, Phialemonium obovatum, Phanerochaete chrysosporium and a combination of Ph. chrysosporium and A. pullulans. After 12 weeks of incubation, oak chips (2 g L^?1) were macerated in a red wine for 17 days. Gas chromatography/mass spectrometry and high‐performance liquid chromatography were used to evaluate 14 compounds, namely furfural, furfuryl alcohol, guaiacol, syringol, cis‐β‐methyl‐γ‐octalactone, 2‐phenylethanol, 4‐vinylguaiacol, benzyl alcohol, 2,3‐butanediol, γ‐butyrolactone, benzaldehyde, 4‐ethylguaiacol, gallic acid and ellagic acid. RESULTS: The microfungal treatments increased the concentration of some components. In particular, P. purpurogenum resulted in a significant improvement in the levels of guaiacol, furfural, syringol, furfuryl alcohol and 2‐phenylethanol. CONCLUSION: Penicillium purpurogenum and Ph. chrysosporium showed a constant trend (enrichment of furfural and benzaldehyde) independent to some extent of the medium used for chip treatment. Copyright © 2010 Society of Chemical Industry     

Phenolic compounds in oak wood extracts used in the ageing of brandies

The oak wood extracts used in brandy production are extremely varied because of the different ways in which they are made: by infusion, by boiling or by maceration, with or without prior physical or chemical treatment of the wood. Such extracts release a large quantity of phenolic compounds and a very small amount of partially degraded lignin into the brandy, unlike spirits aged in oak barrels. Among monomer compounds derived from lignin, the presence of vanillic and syringic acids, vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde can be noted. In the wood extracts, phenolic compounds and aromatic acids frequently dominate the ligno-complex and aromatic aldehydes respectively, which is not the case in brandies. Two samples of liquid extracts of oak wood displayed statistically aberrant vanillin contents.     

The influence of malolactic fermentation and Oenococcus oeni strain on glycosidic aroma precursors and related volatile compounds of red wine

Free and glycosidically bound volatile compounds of red wine were measured after malolactic fermentation (MLF) with four different commercial starter cultures of Oenococcus oeni. MLF resulted in a significant decrease in the concentration of total glycosides, expressed as phenol‐free glycosyl glucose. Gas chromatographic analyses of wine enzyme hydrolysates showed that the extent of hydrolysis of glycosides during MLF was dependent on both bacterial strain and chemical structure of the substrate. The highest decrease was observed for glycosidic precursors of primary terpene alcohols. Glycoside‐related aroma compounds such as linalool, farnesol, and β‐damascenone were increased after MLF with all the bacterial strains tested. Two of the strains were also able to release significant amounts of vinylphenols during MLF. Copyright © 2006 Society of Chemical Industry     

The effect of oak wood source, location of seasoning and coopering on the composition of volatile compounds in oak-matured wines

The effect of geographical origin and place of seasoning and coopering of oakwood on the concentration of 20 compounds extracted into, or formed in, Chardonnay, Cabernet Sauvignon and model wines during barrel maturation is described. The oak from which the barrels were fabricated was sourced from the Vosges and Limousin regions and the Tronçais forest in France, and from Ohio in the USA, and was seasoned in either Australia, France or the USA. Wines matured in Vosges oak barrels contained the highest concentrations of cis and trans- oak lactone and eugenol. The Limousin oak barrels imparted lower levels of cis- oak lactone and eugenol to the wines than did the other French oaks. However, the Limousin-oaked wines were richer in these compounds than the American-oaked wines. These results reflected the previously reported composition profiles of the oak-wood from which the barrels were fabricated. Oak seasoned and coopered in Australia generally imparted more cis- oak lactone, eugenol and the coopering products vanillin and furfural into the wines than did the oak seasoned in France or the USA. Although medium toast had been specified for all barrels, there was considerable variability in the concentration of compounds formed by coopering in the wines. Apparent random microbiological activity in the wines also contributed substantially to variation in wine composition. As a likely result of coopering and microbiological variability, few consistent origin or seasoning effects on the compounds resulting from coopering or microbiological action during oak maturation were observed.     

基于神经网络的山楂红酒香气成分色谱保留值的研究

为研究山楂红酒中香气成分的性质,预测其色谱保留时间,采用MATLAB软件有关自编程序,运算得到了山楂红酒中香气成分的分子价连接指数（mXtV）和电拓扑状态指数（Ei）。通过优化筛选,确定了分子价连接性指数的0XpV、1XpV和4XpV、电拓扑状态指数的E1和E12共5个参数,并建立了山楂红酒中香气成分色谱保留时间的定量构效关系模型,其相关系数为0.979,模型具有较强的稳定性和预测能力。将这5个参数作为反向传播算法（BP）神经网络的输入层变量,香气成分的色谱保留时间作为输出层变量,采用5∶5∶1的网络结构,获得了令人满意的神经网络预测模型,模型总相关系数为0.998,得到的色谱保留时间的预测值与实验值颇为吻合,相对平均误差为3.31%。结果表明,山楂红酒中香气成分的色谱保留时间与5种结构参数之间呈现良好的非线性关系,模型较好地揭示了香气成分色谱保留时间的递变规律。     

The effects of size, temperature and air contact on the outcome of heating oak fragments

The concentrations of the important oak aroma volatiles guaiacol, 4-methylguaiacol cis - and trans -oak lactone and vanillin in extracts of French and American oak heated under various conditions were measured using stable isotope dilution analyses coupled with gas chromatography-mass spectrometry. Heating resulted in marked increases in the concentrations of guaiacol, 4-methylguaiacol and vanillin, with more formed at higher temperature. Approximately twice as much guaiacol and 4-methylguaiacol and two to five times as much vanillin were formed by heating in the presence of air compared to heating under argon. Oak lactone concentration was less affected by heating. The effects of heating different sized oak pieces were investigated for French and American oak samples. Compared to heating larger oak pieces, heating smaller fragments of oak generated up to twice as much guaiacol and 4-methylguaiacol and two to four times as much vanillin at 235^oC for both French and American oak. This effect is ascribed to the exposure of a greater surface area of oak to air when smaller fragments are heated. Variable effects were observed for cis - and trans -oak lactone. Variation in chip size, as well as heating time and temperature, is clearly one way of obtaining different aroma profiles from oak products.