Extraction/oxidation kinetics of low molecular weight compounds in wine brandy resulting from different ageing technologies

This study provides innovative information on the influence of new technologies of ageing (stainless steel tanks with wood staves or wood tablets of chestnut or Limousin oak), in comparison with traditional technology (oak wooden barrels), on the extraction/oxidation kinetics of low molecular weight compounds of wine brandy. The brandy was sampled and analysed by HPLC during the first year of ageing. The results show that most of the compounds tend to increase over the time, but their extraction/oxidation kinetics depend on the ageing technology. The wooden barrels promote greater enrichment in the majority of the compounds. However, gallic acid, ellagic acid and syringaldehyde, and vanillin and 5-methylfurfural, which are strong antioxidants and key-odourant compounds, respectively, present higher contents in the brandy aged with the alternative technologies. Chestnut proves to be a suitable alternative to Limousin oak for the ageing of brandy in all the studied technologies, inducing faster evolution and high quality.     

Maturation related phenolic compounds in cachaça aged in new oak barrels

Aging cachaça in wooden barrels improves its chemical and sensory profile and adds quality. Maturation of distilled spirits is influenced by factors such as the species of wood to make the barrels, degree of internal toasting, number of uses of the barrel and aging time. The level of maturation of distillates can be determined based on the concentration of age marker phenolic compounds extracted from the lignin of the wooden barrel, as well as their relationships with each other. This study characterises the aging process of cachaça by analysing the mechanism of lignin degradation during maturation in new oak barrels for up to 60 months in order to establish the relationship between the age of the distillate and the content of phenolic compounds extracted from the wood. The evaluation was based on the analyses of liginin derived compounds using high‐performance liquid chromatography. The level of maturation of aged cachaça can be characterised by evaluating the low molecular weight lignin‐derived phenolic substances. The total amount of benzoic acids (vanillic and syringic acids) can be taken into consideration for predicting the level of maturation of distillates. Based on the composition of maturation related congeners, it is likely that for cachaça, each year of aging in new oak barrels corresponds to approximately five years of aging for spirits in general. © 2020 The Institute of Brewing & Distilling     

应用液液萃取分析中度烘烤橡木片中挥发性化合物

运用液液萃取与气相色谱-质谱联用技术,研究美国、法国与中国中度烘烤程度橡木片的挥发性化合物。共分离和检测出85种挥发性化合物,包括2种萜烯醇类、1种醛类、7种有机酸类、2种酯类、3种内酯类、7种芳香族类、6种酮类、15种呋喃类、34种酚类,以及8种其他化合物。酚类化合物在橡木中种类较多,浓度较高。定量结果表明,丁香醛、香兰素、糠醛、5-羟甲基糠醛等物质质量浓度较高,对橡木的整体风味影响较大。从呋喃类、橡木内酯、香兰素和丁香醛等化合物比较看,中国橡木与美国橡木类似。     

Aromatic potential of Castanea sativa Mill. compared to Quercus species to be used in cooperage

The composition of volatile and semi-volatile compounds of chestnut (Castanea sativa Mill.) was studied and compared to oak wood species frequently used in cooperage (Quercus alba, Quercus petraea, Quercus robur and Quercus pyrenaica) to evaluate its aromatic potential. Chestnut was found to be a suitable wood for use in ageing processes, based on the large, diverse number of detected compounds (e.g., lactones, furanic compounds, terpenes, lignin derivatives and triterpenic compounds). Chestnut wood possessed high levels of volatile phenols and phenolic aldehydes, specifically vanillin and its derivatives. Each wood species exhibited a characteristic, quantifiable composition of volatile compounds, and therefore, the sensorial profile of each wood species is expected to be different. The levels of certain volatile compounds were also useful for discriminating among the studied wood species.     

Hydrolysis of glycosidically bound flavour compounds from oak wood by Oenococcus oeni

Malolactic fermentation (MLF), which is conducted by lactic acid bacteria (LAB), has a significant influence on the stability and organoleptic quality of wine. Recent studies have shown that when MLF is carried out in oak wood barrels, LAB were also able to interact with wood and increase volatile compound contents such as vanillin during MLF. The release of these compounds indicates that LAB may convert vanillin precursors present in oak wood. In this work, the effect of commercial glycosidases on the released vanillin was firstly studied. This aldehyde is present in wood extracts in monoglycosidic forms where the major glycones are arabinose and xylose. Other aglycons released during MLF in barrels, syringaldehyde and whisky-lactones, can be considered as other sources of aroma. Secondly, strains selected with high activities toward glycoside substrates could hydrolyse vanillin glycoside precursors from oak wood with the same efficiency as commercial enzymes.     

Analysis of lignin from oak casks used for the maturation of Scotch whisky

Wood from four types of casks used for the maturation of Scotch whisky was analysed for free vanillin, syringaldehyde, vanillic and syringic acids and for milled wood lignin. Degradation of wood lignin by acidolysis was used to estimate the proportion of intact β-aryl ether linkages present. The yield of milled wood lignin was unaffected by repeated cask use. A comparison of acidolysis yields and the analysis of spirit matured for 3 years in each of the four types of cask indicated that the majority of β-aryl ether linkages in oak lignin are resistant to spirit hydrolysis and that cask exhaustion was not accompanied by significant delignification. Significant reductions in the concentrations of free guaiacyl and syringyl compounds were recorded for used casks and proved the best indicator of cask exhaustion.     

Changes in wood extractives from oak cask staves through maturation of scotch malt whisky

Cask staves, prepared from American white oak, Quercus alba, were obtained from unused, new charred Bourbon, used Bourbon, first-fill Scotch and exhausted Scotch casks. The aim of the experiment was to determine the effect of repeated maturations of whisky on concentration and location of phenolic extractives in the cask wood. Contents of vanillic and syringic acids and the respective aldehydes, arising from hydrolysis of guaiacyl-syringyl lignin, and whisky lactones (cis- and trans-β-methyl-γ-octalactone), arising from charring, were determined. Staves were sampled at 5 mm intervals from the inner char surface to 25 mm depth and wood extracted with chloroform, heptane and aqueous ethanol. Contents of material absorbing at 520 nm, total phenols and vanillic and syringic acids, vanillin and syringaldehyde, were determined by high-performance liquid chromatography; both isomers of whisky lactone were quantified by high-resolution gas chromatography. New cask wood had a maximum for coloured material in the char layer, but maxima for other compounds at 5 mm below the char. As casks were reused in maturations of whiskies, the contents of aromatic aldehydes and acids were reduced in the first 20 mm of the wood and maxima for both acids and aldehydes shifted towards the centre of the staves. This suggested that repeated exposure to aqueous ethanol resulted in compositional changes in the lignin in the wood. The newly charred wood had a maximum for cis-β-methyl-γ-octalactone at 5 mm below the char and the trans isomer at 15 mm. In the first Bourbon maturation both isomers were largely depleted and with successive extractions the maxima moved into the cask until in the exhausted cask wood no lactone was detected.     

A study of the antioxidant capacity of oak wood used in wine ageing and the correlation with polyphenol composition

The antioxidant capacity of oak wood used in the ageing of wine was studied by four different methods: measurement of scavenging capacity against a given radical (ABTS, DPPH), oxygen radical absorbance capacity (ORAC) and the ferric reducing antioxidant power (FRAP). Although the four methods tested gave comparable results for the antioxidant capacity measured in oak wood extracts, the ORAC method gave results with some differences compared to the other methods. Non-toasted oak wood samples displayed more antioxidant power than toasted ones due to differences in the polyphenol composition. A correlation analysis revealed that ellagitannins were the compounds mainly responsible for the antioxidant capacity of oak wood. Some phenolic acids, mainly gallic acid, also showed a significant correlation with antioxidant capacity.     

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     

Effect of ellagitannins,ellagic acid and volatile compounds from oak wood on the (+)‐catechin,procyanidin B1 and malvidin‐3‐glucoside content of model wines

Background and Aims: During ageing in oak barrels, wine undergoes changes because of the release of polyphenols and other molecules from wood. The aim of this study was to evaluate the influence of some oak wood‐derived volatile compounds, ellagic acid and oak wood extracts on the levels of (+)‐catechin, procyanidin B1 and malvidin‐3‐glucoside. Methods and Results: Phenolics and the oak wood derived volatile compounds studied were quantified by HPLC and by GC, respectively. Additionally, the new compounds formed in the solutions were characterised by their spectral properties. Ellagic acid and/or oak wood extracts slowed the decline in the levels of (+)‐catechin and procyanidin B1. In contrast, the decrease in malvidin‐3‐glucoside was more pronounced in the presence of ellagic acid and oak wood chip extracts. Furfural slowed (+)‐catechin degradation, while breakdown of malvidin‐3‐glucoside was slightly more pronounced in the presence of guaiacol, furfural, vanillin and eugenol. (+)‐Catechin, procyanidin B1 and malvidin‐3‐glucoside did not significantly affect the rate of the degradation of ellagitannins during the storage time studied. Finally, new HPLC peaks were detected in the solutions containing (+)‐catechin and ellagic acid, as well as with malvidin‐3‐glucoside with ellagic acid and oak wood extract. Conclusions: Malvidin 3‐glucoside and (+)‐catechin and procyanidin B1 presented distinct behaviours during time in the presence of volatile and non‐volatile compounds from oak wood. Significance of the Study: This work points out the importance of oak wood components in the degradation of anthocyanins and tannins, as well as the reactions that occur during the ageing of red wine.     

Interactions of phenolic and volatile compounds with yeast lees,commercial yeast derivatives and non toasted chips in model solutions and young red wines

Ageing of wines on lees, the use of commercial yeast derivative products and the addition of oak chips to wine permit the release of different compounds such as mannoproteins and polysaccharides into wines during yeast autolysis. These compounds released can interact with phenolic compounds and/or aromatic compounds, also modifying wine sensory perception. For that reason, the aim of this work was to evaluate the interaction of phenolic and volatile compounds of wines with yeast lees, non-toasted oak wood chips and different commercial yeast derivative preparations in model wine solutions and in a real red wine. The results found in this study have shown that most of the phenolic and volatile compounds studied are adsorbed by wood and bound by lees in model wine solutions. However, in the model wines in general, the commercial yeast derivative products studied only interacted with the volatile compounds but not with the phenolic compounds. The adsorption of the phenolic compounds occurred in the first 15 days of treatment, remaining constant for 2 months; however, in the case of volatile compounds, these compounds initially displayed a retention effect, but after 30–60 days, the release of the previously bound compounds was instigated. The adsorption effect on the phenolic and volatile compounds in the model wine solution was not always the same as in the red wine studied, which highlights the important presence of other wine compounds in these interactions.     

Role of Organic Acids in Maturation of Distilled Spirits in Oak Casks

Maturation of whiskies and brandies in oak casks proceeds by reducing the perception of less desirable aromas of new distillates. During maturation, extraction of wood components increases the solubility of distillate compounds which reduces their headspace concentration above the matured spirit. The origins of this interaction are changes in aggregation of ethanol due to increases in contents of organic acids. During wood maturation organic acid concentrations in spirits increase as a result of extraction from cask wood, oxidation of ethanol and evaporation of ethanol and water. The effect of such changes was simulated using a model whisky ester in aqueous solutions of ethanol with acetic acid, oak wood extracts and acid fractions from new and matured Scotch malt distillates.     

Changes in contents of phenolic compounds during maturing of barrique red wines

Concentrations of derivatives of benzoic and cinnamic acids and furaldehyde were studied during maturing of a red wine (a mixture of Cabernet Sauvignon and Merlot) in barrique barrels (Quercus robur). Samples were taken at three-week intervals over 6 months. The influence of degree of toasting of the wood on the amount of phenolic compounds in barrique wine was also investigated. The samples were pre-separated using a solid-phase extraction on an RP 105 polymeric sorbent and analysed by high-performance liquid chromatography with UV-DAD detection. Gallic, protocatechuic, p-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, ferulic, benzoic and ellagic acids and p-hydroxybenzaldehyde, vanillin, 2-furaldehyde, 5-methoxy-2-furaldehyde and 5-methyl-2-furaldehyde were identified in the extracts of natural and toasted wood chips and in the extracts of the wine. Syringaldehyde was identified only in the extracts of the toasted wood chips. Ellagic acid can be regarded as a characteristic compound of barrique wine ageing and its constant level during some periods could become a marker of maturity of barrique wines. Due to the absence of furaldehydes in natural wines, these compounds can be considered as typical components of barrique wines and so they can serve as a marker of authenticity of barrique wines.     

Interaction of Œnococcus œni and oak wood compounds

The purpose of this work was to study the effect of wood extract on Œnococcus œni growth in synthetic media and its influence on the concentration of volatile compounds when lactic acid bacteria (LAB) are present. Analytical results and sensorial consequences are described when malolactic fermentation was performed in tank or barrels. Using gas chromatography-mass spectrometry, the modifications in oaklactone, eugenol, isoeugenol and vanillin levels were monitored in the presence of Œ. œni. These volatile compounds are known to have powerful characteristic odors (woody, spicy, smoky and vanillin) and to play a role in wine aroma. LAB cultures were performed in synthetic media supplemented with oak wood shavings or extracts. The bacterial growth rate was lower in the absence of heated shavings.This study shows that LAB, especially Œ. œni, are able to interact with wood and form volatile compounds. In laboratory medium, the heating of wood favored bacterial viability more than the simple addition of wood shavings. This is the first demonstration of the capacity of wine Œ. œni to enhance volatile compounds from wood.     

Optimisation,characterisation and quantification of phenolic compounds in olive cake

The phenolic compounds in extracts from pressed olive cake were investigated. Free phenolic compounds were extracted from olive cake using methanol. To liberate bound phenolic compounds, the olive cake was subjected to basic and acidic hydrolysis followed by methanol extraction. The individual phenolic compounds and antioxidant activity of the extracts were determined. The highest total phenolic content and antioxidant activity were obtained using methanol extraction for 12 h at 70 °C. The RP-HPLC profiles for full-fat and defatted olive cake showed that protocatechuic acid, hydroxybenzoic acid, sinapic acid, p-coumaric acid, rutin and hesperidin were the predominant free phenolic compounds. Meanwhile, syringic acid, sinapic acid, caffeic acid and protocatechuic acid were the predominant bound phenolic acids. A positive correlation was observed between total phenolic content and antioxidant activity. The results indicated that most of the phenolic compounds in olive products were present in their free forms (75–90% of total phenolic content), while bound phenolic compounds were only a small proportion (10–25%) of total phenolic content.     

Astringency,bitterness and color changes in dry red wines before and during oak barrel aging: An updated phenolic perspective review

To understand effects of using oak barrels on the astringency, bitterness and color of dry red wines, phenolic reactions in wines before and after barrel aging are reviewed in this paper, which has been divided into three sections. The first section includes an introduction to chemical reactivities of grape-derived phenolic compounds, a summary of the phenolic reactions that occur in dry red wines before barrel aging, and a discussion of the effects of these reactions on wine astringency, bitterness and color. The second section introduces barrel types that determine the oak barrel constituents in wines (primarily oak aldehydes and ellagitannins) and presents reactions between the oak constituents and grape-derived phenolic compounds that may modulate wine astringency, bitterness and color. The final section illustrates the chemical differences between basic oxidation and over-oxidation in wines, discusses oxygen consumption kinetics in wines during barrel aging by comparing different oxygen consumption kinetics observed previously by others, and speculates on the possible preliminary phenolic reactions that occur in dry red wines during oak barrel aging that soften tannins and stabilize pigments via basic oxidation. Additionally, sulfur dioxide (SO₂) addition during barrel aging and suitability of adopting oak barrels for aging wines are briefly discussed.     

GC–MS and GC–olfactometry analysis of aroma compounds in a representative organic aroma extract from cured vanilla (Vanilla planifolia G. Jackson) beans

Volatile compounds from cured vanilla beans were extracted using organic solvents. Sensory analysis showed that the aromatic extract obtained with a pentane/ether (1/1 v/v) solvent mixture provided the extract most representative of vanilla bean flavour. Sixty-five volatiles were identified in a pentane/ether extract by GC–MS analysis. Aromatic acids, aliphatic acids and phenolic compounds were the major volatiles. By GC–O analysis of the pentane/ether extract, 26 odour-active compounds were detected. The compounds guaiacol, 4-methylguaiacol, acetovanillone and vanillyl alcohol, found at much lower concentrations in vanilla beans than vanillin, proved to be as intense as vanillin.     

Cachaça stored in casks newly constructed of oak (Quercus sp.), amburana (Amburana cearensis), jatoba (Hymenaeae carbouril), balsam (Myroxylon peruiferum) and peroba (Paratecoma peroba): alcohol content,phenol composition,colour intensity and dry extract

Aging is the last stage of the cachaça production process. The containers used for aging are wooden barrels and casks, which act as a semi‐permeable membrane, allowing the passage of alcohol and water vapours. This passage is a function of the relative humidity and the temperature of the storage location. The wood traditionally used in Brazil is oak. However, various native woods of Brazilian origin have been used in the manufacture of barrels. The principal compounds extracted from wood by the distillates are volatile compounds, phenolic compounds, tannic substances, sugars, glycerol and non‐volatile organic acids. The objectives of this study were to evaluate and compare the phenolic substances found in cachaça stored in recently constructed oak, amburana, Jatoba, balsam and peroba casks. We evaluated some physicochemical parameters that changed during the storage process. After 12 months of storage, we observed a decrease in alcohol content and an increase in dry extract. An increase in total phenolic compounds and colour intensity was observed, and there was a strong linear correlation between total phenolic compounds, solids and colour intensity. According to the results for the phenols analysed by HPLC, a progressive increase in all the compounds and a heterogeneity in all woods used for the storage of beverages were observed. Copyright © 2017 The Institute of Brewing & Distilling     

Synergistic and suppressive effects of dietary phenolic acids and other phytochemicals from cereal extracts on nuclear factor kappa B activity

In this study the combinatorial action of the main phenolic acids (ferulic, caffeic, p-coumaric and sinapic acids) found in extracts of free (ME) and bound phenolic acids (HE) from oat, barley and wheat flour on the modulation of NF-κB activity was investigated. The results show that combination of phenolic acids in low concentrations (<0.1 μg/ml) has a significant synergistic, or enhanced effect, on NF-κB activity, while their combination in high concentrations (0.3–70 μg/ml) helps to suppress the strong effect obtained by individual solutions of ferulic and p-coumaric acids. The modulation of NF-κB activity observed by HE extracts is the effect of combinatorial action of the phenolic acids present therein, while the modulation of NF-κB activity observed with ME extracts is the result of combinatorial action of phenolic acids together with other phenolic compounds present in the extracts. These results increase the knowledge about the health promoting effect from cereal consumption and dietary phenolic acids.