Alcohol Acetate Research Articles

Effect of alternative techniques to ageing on lees and use of non-toasted oak chips in alcoholic fermentation on the aromatic composition of red wine

The aim of this work was to evaluate the effect of different enological treatments on the volatile composition of red wine: ageing on lees with and without adding β-glucanase enzymes; the use of a commercial yeast derivative with and without β-glucanase enzymes; and the use of non-toasted chips in fermentation. The results indicated that the presence of chips during the fermentation enhanced the formation of 2-phenylethanol, ethyl esters and fusel alcohol acetates, but affected the levels of some of the lactones and volatile phenols studied negatively. In addition, it was found that wine lees and commercial yeast derivatives can bind some of the volatile compounds studied, mainly ethyl esters and fusel alcohol acetates. After 6 months in bottle, in general, the differences found between the control wine and wines fermented with chips were maintained. However, between the control wine and the wines treated with natural or commercial yeast, the differences disappeared, although not for all the compounds studied. Finally, an important effect of the addition of β-glucanase enzymes was not observed.

Flavouring Group Evaluation 53, Revision 1 (FGE.53Rev1): Consideration of phenethyl alcohol, aldehyde, acid and related acetals and esters evaluated by JECFA (59th meeting) and structurally related to phenethyl alcohol, aldehyde, esters and related phenylacetic acid esters evaluated by EFSA in FGE.14Rev1 (2009) and one phenoxyethyl ester evaluated in FGE.23Rev1 (2008)

Flavouring Group Evaluation 53, Revision 1 (FGE.53Rev1): Consideration of phenethyl alcohol, aldehyde, acid and related acetals and esters evaluated by JECFA (59th meeting) and structurally related to phenethyl alcohol, aldehyde, esters and related phenylacetic acid esters evaluated by EFSA in FGE.14Rev1 (2009) and one phenoxyethyl ester evaluated in FGE.23Rev1 (2008)

Potentialities of two solventless extraction approaches—Stir bar sorptive extraction and headspace solid-phase microextraction for determination of higher alcohol acetates, isoamyl esters and ethyl esters in wines

A stir bar sorptive extraction with liquid desorption followed by large volume injection coupled to gas chromatography–quadrupole mass spectrometry (SBSE-LD/LVI-GC–qMS) was evaluated for the simultaneous determination of higher alcohol acetates (HAA), isoamyl esters (IsoE) and ethyl esters (EE) of fatty acids. The method performance was assessed and compared with other solventless technique, the solid-phase microextraction (SPME) in headspace mode (HS). For both techniques, influential experimental parameters were optimised to provide sensitive and robust methods. The SBSE-LD/LVI methodology was previously optimised in terms of extraction time, influence of ethanol in the matrix, liquid desorption (LD) conditions and instrumental settings. Higher extraction efficiency was obtained using 60 min of extraction time, 10% ethanol content, n-pentane as desorption solvent, 15 min for the back-extraction period, 10 mL min −1 for the solvent vent flow rate and 10 °C for the inlet temperature. For HS-SPME, the fibre coated with 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) afforded highest extraction efficiency, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 25 °C for 60 min under continuous stirring in the presence of sodium chloride (10% (w/v)). Both methodologies showed good linearity over the concentration range tested, with correlation coefficients higher than 0.984 for HS-SPME and 0.982 for SBES-LD approach, for all analytes. A good reproducibility was attained and low detection limits were achieved using both SBSE-LD (0.03–28.96 μg L −1) and HS-SPME (0.02–20.29 μg L −1) methodologies. The quantification limits for SBSE-LD approach ranging from 0.11 to 96.56 μg L −and from 0.06 to 67.63 μg L −1 for HS-SPME. Using the HS-SPME approach an average recovery of about 70% was obtained whilst by using SBSE-LD obtained average recovery were close to 80%. The analytical and procedural advantages and disadvantages of these two methods have been compared. Both analytical methods were used to determine the HAA, IsoE and EE fatty acids content in “Terras Madeirenses” table wines. A total of 16 esters were identified and quantified from the wine extracts by HS-SPME whereas by SBSE-LD technique were found 25 esters which include 2 higher alcohol acetates, 4 isoamyl esters and 19 ethyl esters of fatty acids. Generally SBSE-LD provided higher sensitivity with decreased analysis time.

Binding capacity of brown pigments present in special Spanish sweet wines

Abstract Some special Spanish sweet wines are obtained by addition of a sweetening and coloring agent called grape syrup, which is obtained by heating must to give a dark and highly caramelised liquid, with similar consistency than other syrups. The aim of this work was to establish the influence of the addition of boiled must or “grape syrup” on the aroma and colour of sweet wines focussing specially on the possible binding effect on volatile compounds. The influence of must polyphenols was also studied, so, a wine sweetened with a “grape syrup” free of polyphenols was also elaborated. As it was expected, the addition of grape syrups gave an increase in the levels of furfural related compounds, and sweet wines showed lower concentrations of terpenes, ethyl esters, organic acids and acetates of alcohols than the control wine. The capacity of brown polymers present in grape syrups to bind these volatile compounds is discussed. Furthermore, colour parameters were also studied and significant differences were found for all of them between sweet wines and control wine.

Key Compounds of Provence Rosé Wine Flavor

The aromas of French Provence rosé wines were subject to in-depth gas chromatography and sensory analyses at the Research and Experimentation Center on Rosé Wine (Centre de Recherche et d’Expérimentation sur le Vin Rosé). The study has demonstrated the olfactive contribution of different volatile compounds of fermentative and varietal origins. Dearomatization and reconstitution of flavor has revealed the preponderant character of ethyl esters and higher alcohol acetates, which are simple to determine and are at the origin of the fruity and amylic notes of rosé wines. Moreover, the search for specific varietal compounds—well known in other types of wines—has made it possible to identify some key compounds of rosé wine flavor: two volatile thiols (3-mercaptohexanol and 3-mercaptohexyl acetate), two furanic compounds (furaneol and homofuraneol), and one C13 norisoprenoid (β-damascenone). These compounds have now been measured in most of the experiments conducted at the Center on Rosé Wine and are used as qualitative indicators in evaluation protocols for the exploitation of vines or for rosé winemaking techniques.

Effect of Physical Factors on the Volatile Constituents of Elettaria Cardamomum Fruits

The chemical composition of the essential oil obtained from dried fruits of Elettaria cardamomum Maton. (Zingiberaceae) of Delhi region was analyzed by gas liquid chromatography (GLC) and gas chromatography mass spectrometry (GC-MS). The variations in essential oil components under different physical factors have been determined. The oil was characterized by a large number monoterpenes (97.6 %) constituting 1,8-cineole (89.6 %), cis-ocimene (3.7 %) and α-terpinene (2.2 %) as the major components. Except the volatile oil exposed to sunlight, 1,8-cineole was detected in all the oil samples and its amount varied from 29.4 % in heated oil to 89.4 % in untreated oil. Linalool, thujyl alcohol, limonene-1,2-epoxide, citronellol, trans-pinocarveol, nerol and linalyl acetate were generated when the oil was heated at 110°C. Exposer of the oil with sunlight, enhanced the production of linalyl acetate (17.8 %) and borneol (12.1 %). 1,4-Cineole, pcymene-8-ol and isoborneol were only detected in UV exposed oil while the 2-heptane was only identified in high amounts in silica gel and alumina treated volatile oils.

Evaluation of vinasses from sugarcane molasses distillation as a new source of sugarcane wax

Molasses, a by-product of sugar manufacturing, are the most common raw material for rum manufacturing. During the fermentation and distillation process, vinasses are produced in large quantities and disposed in landfills. In this study, they were evaluated as a new source of sugarcane wax. The chemical composition of the wax was studied by GC-Mass spectroscopy. A series of n-alkanes (C23–C33) and ethyl and methyl esters of fatty acids (palmitate and oleate are the predominant), of phytosterols (stigmasterol, β-sitosterol, campesterol), free fatty acids (C12:0–C36:0), and triglycerides constitute the main components. In addition, 2-ketones (C27–C33), aldehydes (C28, C32, C34), ketosteroids (derivatives of stigmasterol, β-sitosterol, and campesterol), and fatty alcohol acetates (alcohol moiety: C28, C30, C32) were found as minor products.

Changes in aromatic characteristics of Loureiro and Alvarinho wines during maturation

Changes in volatiles during maturation in bottles of monovarietal Vinhos Verdes wines from Loureiro and Alvarinho grape varieties, were followed by chemical and sensory analyses. Young wines and wines matured for 8 and 20 months were studied. The volatiles were determined by gas chromatography–mass spectrometry (GC-MS) after extraction on XAD-2 resin. Straight chain fatty acid ethyl esters and acetates of fusel alcohols decreased quicker for Loureiro wine, while the increase in ethyl esters of branched fatty acids was similar for both varieties. Linalool, Ho-trienol, α-terpineol and β-damascenone could be used to differentiate between each variety. However, linalool decreased to negligible values after 20 months of maturation. β-Damascenone decreased but remained high enough to be useful for differentiating each variety. Sensory analysis indicated a decrease of tropical fruit and tree fruit characters with conservation time for Alvarinho wine, and the opposite for Loureiro; moreover, citrus fruit character decreased in both varieties.

Volatile and Glycosidically Bound Composition of Loureiro and Alvarinho Wines

Composition of Loureiro and Alvarinho wines from the Vinhos Verdes region, regarding free volatile compounds as well as glycosidically bound aroma precursors, was exhaustively determined by gas chromatography—mass spectrometry after adsorption on XAD-2 resin. On the whole, were identified and quantified 120 volatile compounds in the free fraction and 77 glycosidically bound compounds, belonging to C6-compounds, alcohols, fatty acids ethyl esters, esters of organic acids, acetates, monoterpenic alcohols, monoterpenic oxides and diols, C13-norisoprenoids, volatile phenols, volatile fatty acids, and carbonyl compounds. Globally, the wines of the two cultivars present similar composition on volatiles. However, regarding varietal compounds, Loureiro wines were richer than Alvarinho ones with respect to C6-compounds and monoterpenic compounds, occurring the opposite for volatile phenols. It was also demonstrated that wines of both varieties might benefit the aroma reserve, present as glycoconjugates, as it is susceptible of being technologically explored. Linalool, Ho-trienol, (α-terpineol, contributing with fruity and floral notes, and (β-damascenone mostly for Alvarinho, confering tropical fruit notes, are the varietal compounds which may particularly influence the aroma of these wines. Respecting fermentative compounds, Alvarinho is also particularly rich in fatty acids ethyl esters related to lipid metabolism and acetates of fusel alcohols, which can provide it a fruity character; Loureiro contains higher levels of esters of organic acids and 2-phenylethanol, conferring fruity and floral notes. Sensory analysis agreed with chemical analyses showing a pronounced tree and tropical fruit character for Alvarinho wines while Loureiro wines present more intense citrus fruit notes.

Volatile flavour constituent patterns of Terras Madeirenses red wines extracted by dynamic headspace solid‐phase microextraction

A suitable analytical procedure based on static headspace solid-phase microextraction (SPME) followed by thermal desorption gas chromatography-ion trap mass spectrometry detection (GC-(ITD)MS), was developed and applied for the qualitative and semi-quantitative analysis of volatile components of Portuguese Terras Madeirenses red wines. The headspace SPME method was optimised in terms of fibre coating, extraction time, and extraction temperature. The performance of three commercially available SPME fibres, viz. 100 mum polydimethylsiloxane; 85 mum polyacrylate, PA; and 50/30 mum divinylbenzene/carboxen on polydimethylsiloxane, was evaluated and compared. The highest amounts extracted, in terms of the maximum signal recorded for the total volatile composition, were obtained with a PA coating fibre at 30 degrees C during an extraction time of 60 min with a constant stirring at 750 rpm, after saturation of the sample with NaCl (30%, w/v). More than sixty volatile compounds, belonging to different biosynthetic pathways, have been identified, including fatty acid ethyl esters, higher alcohols, fatty acids, higher alcohol acetates, isoamyl esters, carbonyl compounds, and monoterpenols/C(13)-norisoprenoids.

Influence of Prefermentative Treatments to the Major Volatile Compounds of Assyrtiko Wines

A study of the volatile fraction of Assyrtiko wines, using gas chromatography coupled with olfactometry, was realized. Twenty-seven volatile compounds were identified as potent odorants, most of them originating from the fermentation process. Quantification of the major volatile compounds was realized developing a rapid analytical method based on fractionation of a 50 mL wine aliquot using C 18-reversed phase adsorbent. After elution of the volatile compounds with pentane-diethyl ether and concentration under nitrogen, the final wine extract was injected in a gas chromatography-flame ionization detection system. The method allows satisfactory determination of more than 15 volatile compounds of wine. The linearity of the method gave a typical r (2) between 0.990 and 0.999, while reproducibility ranged from 5.1 to 12.2% (as relative standard deviation) with 9.5% as the average. The method was applied to wines produced by Assyrtiko grapes (AOC Santorini), for two consecutive years, to compare the effect of skin contact prior to fermentation and the must clarification process. Direct press and skin contact wines were differentiated analytically; however, highly significant differences were not. Inversely, the differences found between direct press/clarified and nonclarified wines were significant. Wines produced by direct press and clarified must presented significantly higher levels of ethylic esters and fusel alcohol acetates but lower fusel alcohol levels, leading probably to more fruity wines. This difference, between clarified and nonclarified grape musts, was not significant in the case of the wines produced by skin contact of Assyrtiko berries. These findings were validated by preference sensory analysis tests.

Development of a dynamic headspace solid-phase microextraction procedure coupled to GC–qMSD for evaluation the chemical profile in alcoholic beverages

In the present study, a simple and sensitive methodology based on dynamic headspace solid-phase microextraction (HS-SPME) followed by thermal desorption gas chromatography with quadrupole mass detection (GC–qMSD), was developed and optimized for the determination of volatile (VOCs) and semi-volatile (SVOCs) compounds from different alcoholic beverages: wine, beer and whisky. Key experimental factors influencing the equilibrium of the VOCs and SVOCs between the sample and the SPME fibre, as the type of fibre coating, extraction time and temperature, sample stirring and ionic strength, were optimized. The performance of five commercially available SPME fibres was evaluated and compared, namely polydimethylsiloxane (PDMS, 100 μm); polyacrylate (PA, 85 μm); polydimethylsiloxane/divinylbenzene (PDMS/DVB, 65 μm); carboxen™/polydimethylsiloxane (CAR/PDMS, 75 μm) and the divinylbenzene/carboxen on polydimethylsiloxane (DVB/CAR/PDMS, 50/30 μm) (StableFlex). An objective comparison among different alcoholic beverages has been established in terms of qualitative and semi-quantitative differences on volatile and semi-volatile compounds. These compounds belong to several chemical families, including higher alcohols, ethyl esters, fatty acids, higher alcohol acetates, isoamyl esters, carbonyl compounds, furanic compounds, terpenoids, C13-norisoprenoids and volatile phenols. The optimized extraction conditions and GC–qMSD, lead to the successful identification of 44 compounds in white wines, 64 in beers and 104 in whiskys. Some of these compounds were found in all of the examined beverage samples. The main components of the HS-SPME found in white wines were ethyl octanoate (46.9%), ethyl decanoate (30.3%), ethyl 9-decenoate (10.7%), ethyl hexanoate (3.1%), and isoamyl octanoate (2.7%). As for beers, the major compounds were isoamyl alcohol (11.5%), ethyl octanoate (9.1%), isoamyl acetate (8.2%), 2-ethyl-1-hexanol (5.9%), and octanoic acid (5.5%). Ethyl decanoate (58.0%), ethyl octanoate (15.1%), ethyl dodecanoate (13.9%) followed by 3-methyl-1-butanol (1.8%) and isoamyl acetate (1.4%) were found to be the major VOCs in whisky samples.

Synthesis of β‐C‐galacto‐Pyranosides with Fluorine on the Pseudoanomeric Substituent.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Synthesis of Highly Functionalized δ‐Lactone‐Fused Cyclopentanoids.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Highly Enantioselective Synthesis of Arylaliphatic Tertiary Alcohols using Mutants of an Esterase from Bacillus subtilis

AbstractThe kinetic resolution of a series of acetates of arylaliphatic tertiary alcohols was studied using recombinant esterase variants from Bacillus subtilis (BS2) expressed in E. coli. Highest enantioselectivities (E>100) were achieved in the synthesis of 1,1,1‐trifluoro‐2‐phenylbut‐3‐yn‐2‐ol and three para‐substituted analogues using BS2 mutant G105A. With mutant E188D only two compounds were converted with E>100. For a thiophene analogue or compounds with small variations in the aliphatic chain substantially lower conversions and/or enantioselectivity were observed, which also varied with the BS2 variant used. Thus, small changes in the substrate structure and point mutations in the esterase had a remarkable influence on both activity and enantioselectivity.

Synthesis of Highly Functionalized δ-Lactone-Fused Cyclopentanoids

A short and efficient route to δ-lactone-fused cyclopentanoids starting from the easily accessible Diels-Alder adducts between homoallylic alcohol acetates and 1,2,3,4-tetrachloro-5,5-dimethoxycyclopenta-1,3-diene is reported. Since homoallyl alcohols were derived from the corresponding aldehydes RCHO (R = alkyl, aryl) through allyl metal addition, the methodology is broad in scope with regard to the choice of R group. The initially formed 1:1 diastereomeric mixture of adducts were subjected to ruthenium-catalyzed oxidation followed by acid-mediated hydrolysis of the acetate groups to obtain the hemiacetals 6A- E. Alkaline H 2 O 2 -mediated cleavage of the hemiacetals led, after esterification with diazomethane, to a chromatographically separable diastereomeric mixture of 7 and 8 in high overall yield (54-68%).

Synthesis of β-C-galacto-Pyranosides with Fluorine on the Pseudoanomeric Substituent

[reaction: see text] beta-C-galacto-Pyranosides with CHF and CF2 substitutes for the glycosidic oxygen were prepared through a four-step sequence starting from a central 1-thio-1,2-O-isopropylidene acetal alcohol and different alpha-fluoro- and alpha,alpha-difluoro acids. The key step in the synthesis is the oxocarbenium cyclization of an intermediate enol ether-thioacetal to a C1-substituted glycal.

Candidate sex pheromones of the New World screwworm Cochliomyia hominivorax

Five novel homologous acetate derivatives of long-chain secondary alcohols and a related ketone were tested for their efficacy as contact mating stimulants for Cochliomyia hominivorax Coquerel (Diptera: Calliphoridae). Full copulatory behaviour at a high percentage was found in tests with racemic 6-acetoxy-19-methylnonacosane at 2.5-20 microg using fertile males from three strains. Males of two strains responded nearly as well to 7-acetoxy-15-methylnonacosane, but an older strain first colonized in 1992 did not respond to this compound. Few or no copulatory responses were obtained to the other secondary alcohol acetates and a related ketone. These two acetate derivatives are the first sex pheromones identified in a calliphorid fly. The threshold of response was also tested, but could not be pinpointed.

Identification of a metagenome-derived esterase with high enantioselectivity in the kinetic resolution of arylaliphatic tertiary alcohols

35 metagenome-derived esterases bearing a GGG(A)X motif were screened for activity and enantioselectivity in the hydrolysis of a range of tertiary alcohol acetates. Most of the active esterases showed little or no enantioselectivity in the hydrolysis of the terpinyl acetate, linalyl acetate and 3-methylpent-1-yn-3-yl acetate. However, one esterase showed excellent enantioselectivity (E > 100) in the kinetic resolution of 1,1,1-trifluoro-2-phenylbut-3-yn-2-yl acetate as confirmed by a preparative scale reaction.

High-throughput screening of activity and enantioselectivity of esterases

A procedure for the high-throughput screening of esterases is described. This includes enzyme expression in microtiter plates and the measurement of activity and enantioselectivity (E) of the esterase variants using acetates of secondary alcohols as model substrates. Acetic acid released is converted in an enzyme cascade leading to the stoichiometric formation of NADH, which is quantified in a spectrophotometer. The method allows screening of several thousand mutants per day and has already been successfully applied to identify an esterase mutant with an E>100 toward an important building block for organic synthesis. This protocol can also be used for lipases and possibly other hydrolases that are expressed in soluble form in conventional Escherichia coli strains. This protocol can be completed in 3-4 days.