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Quantitative ester analysis in cachaca and distilled spirits by gas chromatography-mass spectrometry (GC-MS)

NASCIMENTO, Eduardo S. P.; CARDOSO, Daniel R.; FRANCO, Douglas W.
Fonte: AMER CHEMICAL SOC Publicador: AMER CHEMICAL SOC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
16.73%
An analytical procedure for the separation and quantification of ethyl acetate, ethyl butyrate, ethyl hexanoate, ethyl lactate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, isoamyl octanoate, and ethyl laurate in cachaca, rum, and whisky by direct injection gas chromatography-mass spectrometry was developed. The analytical method is simple, selective, and appropriated for the determination of esters in distilled spirits. The limit of detection ranged from 29 (ethyl hexanoate) to 530 (ethyl acetate) mu g L-1, whereas the standard deviation for repeatability was between 0.774% (ethyl hexanoate) and 5.05% (isoamyl octanoate). Relative standard deviation values for accuracy vary from 90.3 to 98.5% for ethyl butyrate and ethyl acetate, respectively. Ethyl acetate was shown to be the major ester in cachaca (median content of 22.6 mg 100 mL(-1) anhydrous alcohol), followed by ethyl lactate (median content of 8.32 mg 100 mL(-1) anhydrous alcohol). Cachaca produced in copper and hybrid alembic present a higher content of ethyl acetate and ethyl lactate than those produced in a stainless-steel column, whereas cachaca produced by distillation in a stainless-steel column present a higher content of ethyl octanoate, ethyl decanoate, and ethyl laurate. As expected...

Chemical profile of rums as a function of their origin. The use of chemometric techniques for their identification

SAMPAIO, Olivia Moreira; RECHE, Roni Vicente; FRANCO, Douglas Wagner
Fonte: AMER CHEMICAL SOC Publicador: AMER CHEMICAL SOC
Tipo: Artigo de Revista Científica
ENG
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26.69%
To identify chemical descriptors to distinguish Cuban from non-Cuban rums, analyses of 44 samples of rum from 15 different countries are described. To provide the chemical descriptors, analyses of the the mineral fraction, phenolic compounds, caramel, alcohols, acetic acid, ethyl acetate, ketones, and aldehydes were carried out. The analytical data were treated through the following chemometric methods: principal component analysis (PCA), partial least square-discriminate analysis (PLS-DA), and linear discriminate analysis (LDA). These analyses indicated 23 analytes as relevant chemical descriptors for the separation of rums into two distinct groups. The possibility of clustering the rum samples investigated through PCA analysis led to an accumulative percentage of 70.4% in the first three principal components, and isoamyl alcohol, n-propyl alcohol, copper, iron, 2-furfuraldehyde (furfuraldehyde), phenylmethanal (benzaldehyde), epicatechin, and vanillin were used as chemical descriptors. By applying the PLS-DA technique to the whole set of analytical data, the following analytes have been selected as descriptors: acetone, sec-butyl alcohol, isobutyl alcohol, ethyl acetate, methanol, isoamyl alcohol, magnesium, sodium, lead, iron, manganese...

Ésteres em aguardente de cana: seu perfil; Esters in sugar cane spirits: its profile

Nascimento, Eduardo Sanches Pereira do
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 17/04/2007 PT
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A presença de nove ésteres (acetato de etila, butanoato de etila, hexanoato de etila, lactato de etila, octanoato de etila, nonanoato de etila, decanoato de etila, octanoato de isoamila e dodecanoato de etila) foi investigada por cromatografia gasosa hifenada à espectrometria de massas via injeção direta de amostras (ID-CG-EM). Cento e trinta e seis amostras de aguardente de cana foram coletadas durante sua destilação em diferentes produtores em diferentes cidades localizadas no interior do estado de São Paulo. Também foram analisadas 21 amostras de cachaça comercial, 10 amostras de rum e 10 amostras de uísque importados e obtidos em lojas "duty free shop". A metodologia analítica desenvolvida para análise de ésteres demonstrou-se apropriada para a determinação destes compostos em bebidas destiladas, sendo simples (injeção direta), seletiva e relativamente rápida. Apresentou baixos limites de detecção e quantificação e boa repetibilidade. O acetato de etila é o principal éster presente nas bebidas destiladas seguido pelo lactato de etila. Em todas as amostras de bebidas destiladas analisadas neste trabalho foi detectada a presença do éster lactato etila. A presença deste éster está relacionada com a contaminação do mosto por bactérias (Lactobacillus spp) responsáveis pela fermentação láctica. A concentração de lactato de etila nas amostras de cachaça e rum é muito superior à encontrada nas amostras de uísque. A análise multivariada dos resultados analíticos aplicada ao banco de dados dos ésteres juntamente com as concentrações de carbamato de etila e benzaldeído levaram à formação de dois grupos bem distintos: amostras destiladas em alambiques de cobre e amostras destiladas em colunas de aço inox. Os modelos estatísticos gerados pelas análises exploratórias de PCA...

Compostos de volateis e qualidade de sabor da cachaça.; Volatile composites and quality of flavor of cachaça.

Natalia Soares Janzantti
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/08/2004 PT
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16.73%
A cachaça é a bebida mais consumida no Brasil, com uma produção anual de 1,3 bilhão de litros. Uma boa cachaça, além de atender as exigências legais com relação à sua composição, deve também apresentar qualidade sensorial capaz de satisfazer ou mesmo ultrapassar as expectativas de seus consumidores. Os compostos voláteis como álcoois superiores, ésteres, ácidos carboxílicos e compostos carbonílicos são importantes para o sabor característico das bebidas alcoólicas. A revisão da literatura mostrou que, até o presente momento, não existe um estudo sobre a composição de voláteis de cachaça, abrangendo todas as classes químicas presentes na bebida, assim como não se conhece os compostos voláteis odoríferos importantes para a sua qualidade sensorial. Para isso, um método foi desenvolvido em extração em fase sólida para a análise dos compostos voláteis da cachaça por cromatografia gasosa. Os compostos voláteis foram extraídos de uma solução de cachaça/água (1:1) em um cartucho contendo 200 mg de resina Licrolut EN da Merck e a eluição feita com 1,5 mL de diclorometano/dimetil éter (9:1 v/v). O extrato obtido foi representativo da amostra original de cachaça. O método mostrou-se simples...

Estudo do processo de destilação de óleo fúsel; Study of the fusel oil distillation process

Marcela Cravo Ferreira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/03/2012 PT
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26.97%
O óleo fúsel é um resíduo obtido das destilarias de etanol carburante, constituído por uma mistura de álcoois superiores, como álcool isoamílico, álcool isobutílico, dentre outros. Esses álcoois são classificados como congêneres da fermentação alcoólica e devem ser retirados na coluna de retificação, pois tendem a se acumular na mesma. Em países onde há uma grande produção de etanol combustível, como o Brasil, alternativas para a utilização dos resíduos gerados nesse processo são de grande importância para tornar a produção de etanol menos poluidora e mais rentável. O baixo preço do óleo fúsel e seu elevado teor de álcool isoamílico, além do elevado volume de óleo fúsel produzido pelo Brasil anualmente, justificam o desenvolvimento de tecnologias para o fracionamento dessa mistura. Sob o ponto de vista técnico-econômico, a utilização do álcool isoamílico presente no óleo fúsel como precursor de ésteres de aroma, bem como ésteres lubrificantes, torna-se uma alternativa atrativa. Sendo assim, o objetivo desse trabalho foi estudar o processo de destilação industrial do óleo fúsel para obtenção do álcool isoamílico utilizando o simulador Aspen Plus. Em uma primeira etapa, foram realizados experimentos em uma coluna de destilação piloto e os resultados obtidos foram comparados com os simulados para o mesmo processo...

Characterisation of volatile compounds in an alcoholic beverage produced by whey fermentation

Dragone, Giuliano; Mussatto, Solange I.; Oliveira, J. M.; Teixeira, J. A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /02/2009 ENG
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16.73%
An alcoholic beverage (35.4% v/v ethanol) was produced by distillation of the fermented broth obtained by continuous whey fermentation with a lactose-fermenting yeast Kluyveromyces marxianus. Forty volatile compounds were identified in this drink by gas chromatography. Higher alcohols were the most abundant group of volatile compounds present, with isoamyl, isobutyl, 1-propanol, and isopentyl alcohols being found in highest quantities (887, 542, 266, and 176 mg/l, respectively). Ethyl acetate had the highest concentration (138 mg/l) among the esters. Besides higher alcohols and esters, other components, including aldehydes, acids and terpenes were also identified in the whey spirit. Considering that the quality of an alcoholic beverage can be evaluated by the relation between isoamyl alcohol/2-methyl-1-propanol and 2-methyl-1-propanol/1-propanol, which have to be higher than unity, it was concluded that a novel spirit of acceptable organoleptic characteristics can be produced by cheese whey continuous fermentation with K. marxianus.

Monitoring and characterization of yeasts behavior under fermentation processes using technometric approaches

Castro, Cristiana C.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Tese de Doutorado
Publicado em 11/12/2013 ENG
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Tese de doutoramento em Chemical and Biological Engineering; Technometrics concerns on the development and use of statistical methods in different fields, such as biotechnological processes, in order to understand their multivariate and multidimensional complexity. Chemical changes occurring within these processes can be monitored using chemometric tools that combined with bioinformatic methodologies, can provide an enlarged overview of the process, enabling the unbiased study of metabolites and dynamic changes in response to the environmental conditions. For this purpose, different chemometric tools were used, namely relevant principal component analysis (RPCA), multi-way principal component analysis (MPCA), partial least squares logistic regression (PLSLOG) and unfolded partial least squares (U-PLS). Phenotypic and physiological behaviors of three different Saccharomyces cerevisiae strains, a laboratorial S288c, and two industrials CA11 and PE-2, were evaluated under different stress conditions. Toxic and inhibitory conditions were induced by introducing 1.0% (v/v) ethanol, 1-butanol, isopropanol, tert-Amyl alcohol, 0.2% (v/v) furfural and 0.5% (v/v) 5-hydroxymethylfurfural (5-HMF) in batch fermentations with YPD as culture medium. MPCA and PLS-LOG allowed to evidence the different behavior of S288c comparing to PE-2 and CA11...

Heavy sulphur compounds, higher alcohols and esters production profile of Hanseniaspora uvarum and Hanseniaspora guilliermondii grown as pure and mixed cultures in grape must

Moreira, N.; Mendes, F.; Pinho, P. Guedes de; Hogg, T.; Vasconcelos, I.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2008 ENG
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26.45%
Hanseniaspora guilliermondii and Hanseniaspora uvarum were tested in grape must fermentations as pure and mixed starter cultures with Saccharomyces cerevisiae. In pure cultures, the specific growth rates found were 0.29 h⁻¹ for H. uvarum, 0.23 h⁻¹ for H. guilliermondii and 0.18 h⁻¹ for S. cerevisiae. No significant differences were observed between these values and those obtained in mixed cultures. Results presented in this work show that growth of apiculate yeasts during the first days of fermentation enhances the production of desirable compounds, such as esters, and may not have a negative influence on the production of higher alcohols and undesirable heavy sulphur compounds. Growth of apiculate yeasts reduced the total content of higher alcohols in wines, when compared to those produced by a pure culture of S. cerevisiae. Furthermore, the highest levels of 2-phenylethyl acetate were obtained when H. guilliermondii was inoculated in grape musts, whereas H. uvarum increased the isoamyl acetate content of wines. Apiculate yeasts produced high amounts of ethyl acetate; however, the level of this compound decreased in mixed cultures of apiculate yeasts and S. cerevisiae. When S. cerevisiae was used as a starter culture, wines showed higher concentrations of glycerol...

Análise dos álcoois, ésteres e compostos carbonílicos em amostras de óleo fúsel

Pérez,Eduardo R.; Cardoso,Daniel R.; Franco,Douglas W.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2001 PT
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26.45%
Analysis of alcohols, esters and carbonyl compounds were performed using HRGC and HPLC techniques in samples of fusel oils from three different Brazilian alcohol distilleries. High content of isoamyl alcohol (390 g.L-1), isobutyl alcohol (158 g.L-1), ethyl alcohol (28,4 g.L-1), methyl alcohol (16,6 g.L-1) and n-propyl alcohol (11,9 g.L-1) were found. These compounds represent 77 ± 8 % of the approximated weight of a liter of fusel oils. The obtained results show the feasibility of using fusel oils as low-cost raw material for the synthesis of chemicals.

Identification and dosage by HRGC of minor alcohols and esters in Brazilian sugar-cane spirit

Boscolo,Maurício; Bezerra,Cícero W. B.; Cardoso,Daniel R.; Lima Neto,Benedito S.; Franco,Douglas W.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2000 EN
Relevância na Pesquisa
36.94%
The presence of 51 volatile compounds, among alcohols and esters in Brazilian sugar-cane spirit (cachaça), were investigated by high-resolution gas chromatography (HRGC). The following alcohols and esters were identified and quantified: methanol, 1,4-butanodiol, 2-phenylethyl alcohol, amyl alcohol, cetyl alcohol, cynamic alcohol, n-decanol, geraniol, isoamyl alcohol, isobutanol, menthol, n-butanol, n-dodecanol, n-propanol, n-tetradecanol, amyl propionate, ethyl acetate, ethyl benzoate, ethyl heptanoate, isoamyl valerate, methyl propionate, propyl butyrate. The average higher alcohols content (262 mg/100 mL in anhydrous alcohol a.a.) and total esters content (24 mg/100 mL a.a.) in cachaças, are smaller than in other spirits. The average methanol content in cachaças (6 mg/100 mL a.a.) is the same as in rum, but smaller than in wine spirit. No qualitative differences of chemical profile among cachaças have been observed.

Expression Levels of the Yeast Alcohol Acetyltransferase Genes ATF1, Lg-ATF1, and ATF2 Control the Formation of a Broad Range of Volatile Esters

Verstrepen, Kevin J.; Van Laere, Stijn D. M.; Vanderhaegen, Bart M. P.; Derdelinckx, Guy; Dufour, Jean-Pierre; Pretorius, Isak S.; Winderickx, Joris; Thevelein, Johan M.; Delvaux, Freddy R.
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /09/2003 EN
Relevância na Pesquisa
27.12%
Volatile aroma-active esters are responsible for the fruity character of fermented alcoholic beverages such as beer and wine. Esters are produced by fermenting yeast cells in an enzyme-catalyzed intracellular reaction. In order to investigate and compare the roles of the known Saccharomyces cerevisiae alcohol acetyltransferases, Atf1p, Atf2p and Lg-Atf1p, in volatile ester production, the respective genes were either deleted or overexpressed in a laboratory strain and a commercial brewing strain. Subsequently, the ester formation of the transformants was monitored by headspace gas chromatography and gas chromatography combined with mass spectroscopy (GC-MS). Analysis of the fermentation products confirmed that the expression levels of ATF1 and ATF2 greatly affect the production of ethyl acetate and isoamyl acetate. GC-MS analysis revealed that Atf1p and Atf2p are also responsible for the formation of a broad range of less volatile esters, such as propyl acetate, isobutyl acetate, pentyl acetate, hexyl acetate, heptyl acetate, octyl acetate, and phenyl ethyl acetate. With respect to the esters analyzed in this study, Atf2p seemed to play only a minor role compared to Atf1p. The atf1Δ atf2Δ double deletion strain did not form any isoamyl acetate...

Functional Characterization of Enzymes Forming Volatile Esters from Strawberry and Banana[w]

Beekwilder, Jules; Alvarez-Huerta, Mayte; Neef, Evert; Verstappen, Francel W.A.; Bouwmeester, Harro J.; Aharoni, Asaph
Fonte: American Society of Plant Biologists Publicador: American Society of Plant Biologists
Tipo: Artigo de Revista Científica
Publicado em /08/2004 EN
Relevância na Pesquisa
26.55%
Volatile esters are flavor components of the majority of fruits. The last step in their biosynthesis is catalyzed by alcohol acyltransferases (AATs), which link alcohols to acyl moieties. Full-length cDNAs putatively encoding AATs were isolated from fruit of wild strawberry (Fragaria vesca) and banana (Musa sapientum) and compared to the previously isolated SAAT gene from the cultivated strawberry (Fragaria × ananassa). The potential role of these enzymes in fruit flavor formation was assessed. To this end, recombinant enzymes were produced in Escherichia coli, and their activities were analyzed for a variety of alcohol and acyl-CoA substrates. When the results of these activity assays were compared to a phylogenetic analysis of the various members of the acyltransferase family, it was clear that substrate preference could not be predicted on the basis of sequence similarity. In addition, the substrate preference of recombinant enzymes was not necessarily reflected in the representation of esters in the corresponding fruit volatile profiles. This suggests that the specific profile of a given fruit species is to a significant extent determined by the supply of precursors. To study the in planta activity of an alcohol acyltransferase and to assess the potential for metabolic engineering of ester production...

Synthesis of Novel Lipids in Saccharomyces cerevisiae by Heterologous Expression of an Unspecific Bacterial Acyltransferase

Kalscheuer, Rainer; Luftmann, Heinrich; Steinbüchel, Alexander
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /12/2004 EN
Relevância na Pesquisa
26.83%
The bifunctional wax ester synthase/acyl-coenzyme A:diacylglycerol acyltransferase (WS/DGAT) is the key enzyme in storage lipid accumulation in the gram-negative bacterium Acinetobacter calcoaceticus ADP1, mediating wax ester, and to a lesser extent, triacylglycerol (TAG) biosynthesis. Saccharomyces cerevisiae accumulates TAGs and steryl esters as storage lipids. Four genes encoding a DGAT (Dga1p), a phospholipid:diacylglycerol acyltransferase (Lro1p) and two acyl-coenzyme A:sterol acyltransferases (ASATs) (Are1p and Are2p) are involved in the final esterification steps in TAG and steryl ester biosynthesis in this yeast. In the quadruple mutant strain S. cerevisiae H1246, the disruption of DGA1, LRO1, ARE1, and ARE2 leads to an inability to synthesize storage lipids. Heterologous expression of WS/DGAT from A. calcoaceticus ADP1 in S. cerevisiae H1246 restored TAG but not steryl ester biosynthesis, although high levels of ASAT activity could be demonstrated for WS/DGAT expressed in Escherichia coli XL1-Blue in radiometric in vitro assays with cholesterol and ergosterol as substrates. In addition to TAG synthesis, heterologous expression of WS/DGAT in S. cerevisiae H1246 resulted also in the accumulation of fatty acid ethyl esters as well as fatty acid isoamyl esters. In vitro studies confirmed that WS/DGAT is capable of utilizing a broad range of alcohols as substrates comprising long-chain fatty alcohols like hexadecanol as well as short-chain alcohols like ethanol or isoamyl alcohol. This study demonstrated the highly unspecific acyltransferase activity of WS/DGAT from A. calcoaceticus ADP1...

The effect of increased yeast alcohol acetyltransferase and esterase activity on the flavour profiles of wine and distillates

Lilly, M.; Bauer, F.; Lambrechts, M.; Swiegers, J.; Cozzolino, D.; Pretorius, I.
Fonte: John Wiley & Sons Ltd Publicador: John Wiley & Sons Ltd
Tipo: Artigo de Revista Científica
Publicado em //2006 EN
Relevância na Pesquisa
27.13%
The fruity odours of wine are largely derived from the synthesis of esters and higher alcohols during yeast fermentation. The ATF1- and ATF2-encoded alcohol acetyltransferases of S. cerevisiae are responsible for the synthesis of ethyl acetate and isoamyl acetate esters, while the EHT1-encoded ethanol hexanoyl transferase is responsible for synthesizing ethyl caproate. However, esters such as these might be degraded by the IAH1-encoded esterase. The objectives of this study were: (a) to overexpress the genes encoding ester-synthesizing and ester-degrading enzymes in wine yeast; (b) to prepare Colombard table wines and base wines for distillation using these modified strains; and (c) to analyse and compare the ester concentrations and aroma profiles of these wines and distillates. The overexpression of ATF1 significantly increased the concentrations of ethyl acetate, isoamyl acetate, 2-phenylethyl acetate and ethyl caproate, while the overexpression of ATF2 affected the concentrations of ethyl acetate and isoamyl acetate to a lesser degree. The overexpression of IAH1 resulted in a significant decrease in ethyl acetate, isoamyl acetate, hexyl acetate and 2-phenylethyl acetate. The overexpression of EHT1 resulted in a marked increase in ethyl caproate...

Heterologous expression of alcohol acetyltransferase genes in Escherichia coli and Clostridium acetobutylicum for the production of esters

Horton, Catherine Emily
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
26.98%
This thesis focuses on the heterologous expression of alcohol acetyltransferase (AATase) genes in Escherichia coli and Clostridium acetobutylicum for the production of the esters isoamyl acetate, butyl acetate and butyl butyrate. Isoamyl acetate, butyl acetate and butyl butyrate are esters that confer a fruity aroma and taste to the materials in which they are found. AATases are a class of enzymes that have been found to enzymatically catalyze the reaction between alcohols and acyl-CoAs to produce the corresponding ester. Butanol, acetyl-CoA, and butyryl-CoA, the substrates necessary for butyl acetate and butyl butyrate production, are produced in high concentrations by C. acetobutylicum, making it an ideal host for the expression of genes for AATases. Previous studies have characterized AATases in yeast, and expressed them in E. coli, but this is the first report of ester production by AATase activity in C. acetobutylicum . The genes ATF1 and ATF2, encoding AATase I and AATase II from the yeast Saccharomyces cerevisiae, and SAAT encoding a strawberry alcohol acetyltransferase, Saatp, have previously been sequenced. Biochemical studies have shown them to possess AATase activity. For this thesis, ATF1, ATF2, and SAAT were subcloned and expressed in E. coli. Ester production was determined by head-space gas analysis on a gas chromatagraph. AATase I in E. coli cultures and cell-free extracts produced more ester than AATase II did with each alcohol substrate that was investigated. Saatp produced less ester than AATase I...

Simultaneous anaerobic production of isoamyl acetate and succinic acid

San, Ka-Yiu; Sánchez, Ailen; Bennett, George N.; Dittrich, Cheryl Renee
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
26.69%
In vivo method of producing esters from acetyle coA, such as isoamyl acetate and succinate, has been developed by producing null mutants in pathways that use acetyl coA and by overexpressing products that use NADH and in order to maintain the proper redox balance between NADH and NAD+. The method is exemplified with null mutations in ldhA, adhE, ackA-pta and overexpression of pyruvate carboxylase and alcohol acetyltransferase. This strain produces higher levels of both isoamyl acetate and succinate.

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

Rodrigues, F.; Caldeira, M.; Câmara, J. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /02/2008 ENG
Relevância na Pesquisa
27.03%
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...

Volatile flavour constituent patterns of terras madeirenses red wines extracted by dynamic headspace solid‐phase microextraction

Perestrelo, Rosa; Caldeira, Michael; Rodrigues, Freddy
Fonte: Wilei Publicador: Wilei
Tipo: Artigo de Revista Científica
Publicado em //2008 ENG
Relevância na Pesquisa
26.45%
A suitable analytical procedure based on static headspace solid-phase microextraction (SPME) followed by thermal desorption gas chromatography–ion trap mass spectrometry detection (GC–ITDMS), 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 lm polydimethylsiloxane; 85 lm polyacrylate, PA; and 50/30 lm 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 308C 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/C13-norisoprenoids.

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

Perestrelo, R.; Nogueira, J. M. F.; Câmara, J. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /12/2009 ENG
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67.27%
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...

Aromatic profile of white sweet semi-sparkling wine from malvasia di candia aromatica grapes

Montevecchi,G.; Masino,F.; Vasile Simone,G.; Cerretti,E.; Antonelli,A.
Fonte: South African Journal of Enology and Viticulture Publicador: South African Journal of Enology and Viticulture
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2015 EN
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Malvasia di Candia aromatica is an aromatic white grape (Vitis vinifera L.) cultivar that grows in the Emilia-Romagna and Lombardy regions and is used for manufacturing sweet and dry white wines. A study of the gas chromatography analysis of the aromatic profile was carried out during the winemaking process for the production of a sweet semi-sparkling wine. At the end of the monitoring period, free monoterpenic and fermentative compounds characterised the aromatic profile of the wine. Linalool and nerol had a similar concentration, while the main fermentative compounds were the isoamyl alcohols, 2-phenylethanol, medium-chain fatty acids and their corresponding ethyl esters, and isoamyl acetate. All these compounds showed increasing trends during the fermentation process. The amount of linalool at the end of the monitoring period exceeded the threshold of perception, hence contributing to the floral scent of the wine. The higher alcohols (concentration up to 200 mg/L) and their esters also made a pleasant contribution to the aroma definition. Finally, the low temperature of fermentation helped to preserve the varietal aroma and enhanced the production of fermentative compounds, with a corresponding restraint of higher alcohols. This work is a first approach to a study of the sweet semi-sparkling wine (vino frizzante) obtained from Malvasia di Candia aromatica grapes. A more detailed investigation is required to understand how to improve the varietal and fermentative aromas of the wine.