Effect of oak matrix (barrel and toasted chips) on the volatiles in Goji (Lycium Chinese) wine

The extraction efficiencies of volatiles from lightly toasted, medium‐toasted and heavily toasted oak chips with different solvents and the effect of oak matrix (chips and barrel) on the volatile composition of fermented Goji wine were surveyed. Of four different polarity solvents (water, ethanol, ether and dichloromethane), ethanol was the most effective solvent for the extraction of volatiles. The extraction efficiency of volatiles was related to the concentration of ethanol and the toast intensity of chips, and the most efficient extraction configuration was with 30% (v/v) ethanol and medium‐toasted chips. The effect of oak matrix on aroma composition and sensory characteristics of Goji wine was also evaluated. The changes in volatiles were related to the type of oak matrix. Odour activity value analysis and principal component analysis suggested that the effect of medium‐toasted chips on Goji wine was closest to an oak barrel. Sensory analysis showed that caramel, coffee, floral and vanillin flavour were enhanced in medium‐toasted chips, linked to the content of ethyl dihydrocinnamate, vaniliin and eugenol. Copyright © 2017 The Institute of Brewing & Distilling     

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     

Influence of Oak Chips Geographical Origin,Toast Level,Dosage and Aging Time on Volatile Compounds of Apple Cider

The effects of different geographical origin, levels of toasting, dosage and the aging time of oak chips on volatile compounds released into ciders were studied. The oak chips tested were the same size and with three different toast levels (light, medium and heavy) from French, American and Chinese oak. The oak wood chips were immersed in identical ciders. Higher alcohols, acids and esters were determined by headspace (HS)–solid phase microextraction (SPME) and gas chromatography (GC)–mass spectrometry (MS), while oak‐related aroma compounds including trans‐and cis‐oak lactones, guaiacol, 4‐methylguaiacol, furfural, 5‐methylfurfural, vanillin, eugenol and isoeugenol, were determined by liquid‐liquid extraction by means of ultrasound and GC/MS selective ion monitoring (SIM). The results showed that there was little difference between the oak‐related volatile compositions of ciders aged with French oak chips and those aged with American oak chips, but that there were obvious differences with Chinese oak chips. It was observed that oak chips, at medium toasting levels, released the highest concentrations of volatile components into the ciders. Most of the oak‐related volatile aroma compounds extracted had an increase that depended on the oak chip dosage with the exception of guaiacol and furfural.     

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。      

Volatile composition and sensory characteristics of Chardonnay wines treated with American and Hungarian oak chips

Toasted or non-toasted chips of oak woods of different geographical provenances were macerated in Chardonnay wines (4 g/l) during a period of 25 days. Oak lactones were detected in significant quantities in wines treated with American oak. Only trace amounts of oak lactones were detected in the wines treated with Hungarian oak. Toasting of the oaks increased the quantities of the compounds derived from the thermal degradation of lignin: vanillin, eugenol, guaiacol and its derivatives and the pyrolysis of cellulose and hemicellulose: furfural and 5-methyl furfural, and decreased the concentrations of the two isomers of oak lactones. The concentrations of the majority of the volatile compounds did not present statistically significant differences between 15 and 25 days. However, the wines preferred by the tasters and with maximum intensity of the sensory attributes acquired were those treated with oak chips for 25 days. Chemical and sensorial analyses of wines revealed that the effect of the toasting of oak chips on wine characteristics was greater than the type of oak used. All wines studied were positively evaluated by the panellists.     

Statistical differentiation of wines of different geographic origin and aged in barrel according to some volatile components and ethylphenols

The purpose of this paper was to study the effect of wine composition and geographical origin on the accumulation of volatile compounds in barrel-aged wines. Therefore, 267 wines belonging to different origin appellations were analysed. In order to analyse the data, a multivariate statistical technique was applied, that can be quite useful in creating an overall view of the problem in which multiple variables are analysed. Statistical analysis gave four significant factors, accounting for 84.12% of the variance. These factors summarise the information of a group of variables closely correlated to each other. Factor 1 grouped together oak lactones and eugenol, so it was associated with oak barrel type and with toasting of barrels. Factor 2 was associated with ethylphenols, related to wine quality diminution. Factor 3 grouped together guaiacol, furfural, and 5-methylfurfural, and was thus associated with wood thermal degradation; factor 4 was associated with the cis/trans ratio, related to oak origin. Whereas geographical origin of wines affected the accumulation of volatile compounds, the cis/trans ratio was only affected by oak barrel type. Among the tested parameters, alcoholic degree was the enological parameter that had the greatest effect on the accumulation of volatile compounds in wines. Oak lactones were the compounds that were present in all wines, so they could be used as oak ageing indicators.     

Artificial aging of Uva di Troia and Primitivo wines using oak chips inoculated with Penicillium purpurogenum

BACKGROUND: Two red wines (Primitivo and Uva di Troia) treated with oak chips inoculated with Penicillium purpurogenum were analysed in order to assess their contents of furfural, cis‐β‐methyl‐γ‐octalactone, syringol, eugenol, vanillin and 4‐vinylguaiacol. Two different sizes of oak chips (small and big, of length 2 and 8 mm respectively) and two different degrees of toasting (low and high) were used in the study. Aroma compounds were analysed by gas chromatography/mass spectrometry to determine differences among samples after 15 days of chip contact time. RESULTS: Big oak chips inoculated with P. purpurogenum increased the level of 4‐vinylguaiacol, while small oak chips inoculated with P. purpurogenum, in some conditions, increased the level of eugenol. Chip size and degree of toasting also played an important role in the content of eugenol. CONCLUSION: The use of oak chips inoculated with mould might be a promising alternative to barrel aging. Moreover, different fungal inocula could contribute to the enrichment of wine with specific compounds (e.g. 4‐vinylguaiacol and eugenol). Copyright © 2011 Society of Chemical Industry     

Consideration of the influence of aging process,type of wine and oenological classic parameters on the levels of wood volatile compounds present in red wines

The contents of the volatile compounds extracted from wood: cis- and trans-whiskylactones, vanillin, syringaldehyde, furfural, 5-methylfurfural, eugenol, guaiacol, p-ethyl-phenol and p-ethylguaicol have been studied in 12 single-variety wines aged in new American oak barrels. The concentration of these compounds were determined after the following combinations of time in wood and time in bottle: 0 months in wood plus 18 months in bottle, 4 months in wood  + 14 months in bottle, 9 months in wood + 9 moths in bottle and 12 months in wood + 6 months in bottle. According to the composition of the wines, it is possible to conclude in general, that, the extraction of these compounds was faster during the first four or 9 months of aging in wood, depending on the wines. After 12 months of oak maturation, the extraction of these compounds slowed down. Furthermore, the final concentrations of these volatile compounds were different among studied wines. These differences could be related to some of the values of some of their oenological parameters, such as the contents of tartaric acid and sulphur dioxide of each wine.     

Effects of composition,storage time,geographic origin and oak type on the accumulation of some volatile oak compounds and ethylphenols in wines

The aim of this work was to study the effect of different parameters on the accumulation of volatile oak compounds and ethylphenols in red barrel-aged wines. For this, 510 wines, from four different geographic zones and aged for various times in different oak barrel types were analysed. The results of the statistical analysis showed that the compounds were in four groups, accounting for 82.99% of the variance. The enological parameters did not present correlation with any of these four groups. The wines that remained longer in oak barrels presented, in general, higher concentrations of the studied compounds. Three of the four geographic zones were similar to each other. The oak barrel type affected the value of the ratio cis/trans, but it did not affect the accumulation of any of the volatile oak compounds or ethylphenols.     

Criteria to discriminate between wines aged in oak barrels and macerated with oak fragments

Wine aging in barrels is carried out to increase stability and achieve more complex aromas. In the last few years, however, the practice of macerating wine with small fragments of toasted oak (chips) has become increasingly common. This conveys similar tastes, aromas, and wooden notes to the wine as those obtained with traditional barrel aging, but much faster and at a fraction of the cost. Without proper regulation, this could lead to fraud if wine macerated with chips is offered as barrel aged wine.In the present study, 75 volatile compounds have been determined by applying gas chromatography–mass spectrometry (MS) and flame ionization detection (FID). It has been found that compounds directly related to the wood have greater discriminative power for telling apart wines aged in barrels from those macerated with oak fragments, but no single compound permits flawless classification. Therefore, we have studied the effect of the addition of oak fragments of different origins, different oak types, different formats and subjected to different toasting processes on a set of 231 samples from 6 Spanish Denominations of Origin wines (DOs), and compared them to those same wines aged in oak barrels. In light of the results, we have developed a set of criteria which allows distinguishing with high degree of accuracy between wines which have been aged in barrels and those macerated with oak fragments. The application of these criteria to different wines allows correct classification in over 90% of cases.     

Aging marker profile in cachaça is influenced by toasted oak chips

Cachaça is the most important distilled spirit in Brazil and the fourth most consumed in the world. Aging is not mandatory for cachaça. When aging is carried out, casks generally do not undergo the final wood toasting. However the level of thermal degradation of wood influences the formation of new chemical compounds, which are released during the aging process and improve the quality of the spirit. The objective of this study was to verify the influence of origin of wood and toasting intensity of oak chips on the profile of aging markers in cachaça. Staves of oak wood from the forests of Allier, Vosges and Nièvre (France) were milled and screened at 9 mesh. The chips underwent light, medium and heavy toasting. The toasted chips were added to cachaça (1 g/L) and kept in a closed system at room temperature, without agitation, for 15 days. The aging congeners (gallic acid, 5‐hydroxymethylfurfural, furfural, vanillin, vanillic acid, syringaldehyde, sinapaldehyde, syringic acid and coniferaldehyde) were analysed using HPLC. The increase in toasting intensity enhanced the content of the aging markers in cachaça, especially syringic acid, vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde. The generation of aging marker compounds was influenced only by the toasting intensity and not by the origin of the oak wood. Copyright © 2015 The Institute of Brewing & Distilling     

Study of the content in volatile compounds during the aging of sweet Sherry wines obtained from grapes cv. Muscat and fermented under different conditions

Several experiments of aging in oak wood and stainless steel of sweet Sherry wines obtained from grapes cv. Muscat fermented under different enological conditions have been carried out. These wines were periodically sampled and their volatile content was analyzed using SBSE–GC–MS. A sensory study was also carried out. Data were submitted to different statistical techniques. An important influence of the three factors considered, fermentation type, aging type, and aging time, have been observed. In cluster analysis, the grouping obtained demonstrated that the volatile compounds considered possess sufficient explanatory power to detect the type of aging process and differentiate the two yeast strains studied. In the case of the linear discriminant analysis, high percentages of correct classification were obtained for the three factors considered. Taking into account the global volatile profile, the factor “aging type” (oak cask or stainless steel) has demonstrated the highest influence on the volatile content of the wines, with those wines from Experiments D4 and D5 (fermented with S. bayanus) and aged in oak wood clearly differentiated from those ones fermented with S. cerevisiae and aged in wood or stainless steel. From a sensorial point of view, the wines fermented with S. Cerevisiae and aged in wood (D1C and D2C) were the most valued ones.     

Effect of oak wood on the quality of beer

Maturation in wood is an important practice that is widely used in the production of high‐quality beverages. The effect of French oak cubes on young lager beer was studied. Oak cubes (with light, medium or heavy toasting) were added to the beer, which was stored at 0°C for 3 months. Beer samples were analysed monthly, and an acceptance test was performed at the end of 3 months. The content of volatile compounds (aldehydes, esters and higher alcohols) was determined by gas chromatography using a flame ionization detector, and the content of low molecular weight phenolic compounds was determined by high‐performance liquid chromatography. The contents of aldehydes, esters, higher alcohols and wood‐derived compounds increased during the 3‐month maturation period. Lager beer stored with heavily toasted oak cubes had the highest concentration of low‐molecular‐weight phenolic compounds, followed by the beer matured in an oak barrel. These results suggest that beer maturation in wood barrels or with oak cubes changed the composition of their oak‐related aromatic compounds, indicating that interactions between the beer and the wood occurred. Copyright © 2015 The Institute of Brewing & Distilling     

Influence of the botanical origin and toasting level on the ellagitannin content of wines aged in new and used oak barrels

The influence of the botanical origin (French oak: Quercus petraea and American oak: Quercus alba) and different toasting levels (light, medium and heavy) on the ellagitannin content of wines aged in oak barrels has been studied. This took place in two consecutive vintages in order to study what happens after the barrels have been already used for one year with another wine. This study was carried out with two red wines (Cabernet Sauvignon) and with two decolored white wines (Macabeo) from vintages 2012 and 2013 in order to work with a simpler matrix which facilitates chemical analysis. The results show that the botanical origin, toasting level and the number of times that the barrels have been used exert a major influence on the final ellagitannin concentration. In general, the behavior of all the individual ellagitannins was very similar to that described for the total ellagitannins. Briefly, the levels of total ellagitannins concentration in the decolored white wine aged for 12 months in new French barrels ranged between 31.2 mg/L in the lightly toasted and 4.7 mg/L in the heavy toasted. In contrast, these levels were quite lower in American new barrels ranging between 3.6 mg/L and 0.9 mg/L. Finally, the total ellagitannin concentration decreased an average of 63% in the wines aged in the one year used barrels.     

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.     

Use of species other than oak to flavor wine: an exploratory survey

The concept of geographical exclusivity prompted an exploratory survey with toasted woods other than oak to flavor wine. A total of 11 woods and oak (Quercus alba) were cut into chips 20 × 10 × 2.5 mm and toasted at 200 °C for 2 h (light toast) or 210 °C for 3 h (dark). Weight losses and changes in CIE color space were monitored. The toasted chips were infused in unoaked chardonnay (5 g L(-1)) for 2 wk. Parallel infusions were done with model wine (water, ethanol, tartaric acid) adjusted to pH 3.5. Ultraviolet absorbances due to infusion were recorded on the basis that that lignin compounds and their potential pyrolysates are based on phenolic structures that absorb in the ultraviolet range. Weight losses on light and dark toasting were highly variable between species as were color changes, suggesting potential for different flavor outcomes from chemical changes. Ultraviolet absorbance curves were also highly variable showing that different species yielded different quantities of potentially flavor-active phenolic compounds in real and model wine. More absorbing matter was extracted from the light toast treatments, and light toast oak, which demonstrated the greatest weight loss on light toasting, yielded the widest range of ultraviolet-absorbing matter. In an informal sensory trial with the 24 species/toast combinations infused in chardonnay all but one wood, Cupressus macrocarpa, resulted in flavors reminiscent of oaked wines. A hedonic consumer trial with 4 species and oak compared with uninfused chardonnay showed that each of the 4 had potential as a flavorant. Thus, woods unsuited to barrel construction could provide unrealized flavor opportunities in the wine industry, and could extend to flavoring spirits.     

Effect of artificial ageing using different wood chips on the antioxidant activity,resveratrol and catechin concentration,sensory properties and colour of two Greek red wines

Two Greek red wines (Syrah and Cabernet) were artificially aged with different wood chips (white oak, red oak, Turkey oak, chestnut, Bosnian pine, cherry, common juniper, common walnut, white mulberry, black locust and apricot). The influence of each wood species was tested for up to 20 days. The optimum duration for the extraction of total polyphenols was 20 days (Syrah) or 10 days (Cabernet) when chips of white oak, chestnut, cherry, white mulberry, black locust and apricot where used. Resveratrol and catechin concentrations ranged within the limits previously reported in literature. A high antioxidant activity was established after 10 days of artificial ageing. The sensory evaluation showed that the best results were produced by the apricot chips after 5 days (Syrah) or black locust and apricot after 5 days (Cabernet). Colour was seen to increase with both time of ageing and number of wood chips added.     

Volatile composition of Bobal red wines subjected to alcoholic/malolactic fermentation with oak chips

The effect of wood, in the form of oak chips, on the volatile composition of Bobal red wines caused by adding oak chips at different stages of the fermentation process has been studied. Aroma compounds were isolated by solid phase extraction (SPE) for subsequent analysis by gas chromatography–mass spectrometry (GC/MS). Bobal control wine was produced according to traditional winemaking processes, without oak chips. Oak chips were added to the rest of the wines at two dose levels (3 and 6 g/L) at different stages of the winemaking process: at one week during alcoholic fermentation (AF), during malolactic fermentation (MLF) and in young, red Bobal wine. Wines fermented with oak chips during AF showed higher concentrations of the ethyl esters of straight-chain fatty acids and ethyl, hexyl and isoamyl acetates than the control wine. A similar, trend was observed for higher alcohols. Higher concentrations of benzene compounds, oak lactones and furanic compounds were found in wines in contact with oak chips during MLF followed by young Bobal oak wines. These results reveal that the point of addition during the winemaking process and the dose level of oak chips used have a significant effect on the volatile composition of Bobal red wines.