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Paula Guedes De Pinho - One of the best experts on this subject based on the ideXlab platform.

  • development and optimization of a hs spme gc ms methodology to quantify volatile carbonyl compounds in Port Wines
    Food Chemistry, 2019
    Co-Authors: Victor De Freitas, N Moreira, Ana Margarida Araujo, Frank S S Rogerson, I Vasconcelos, Paula Guedes De Pinho
    Abstract:

    Abstract A method based on headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-triple quadrupole/mass spectrometry detection (GC-TQ/MS) with a prior derivatization step with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was developed to quantify carbonyl compounds in different categories of Port Wines. Optimal extraction conditions were obtained incubating 2 ml of wine with 2.3 g/l of PFBHA for 10 min and extracted during 20 min at 32 °C. The method was validated for 38 carbonyl compounds (alkanals, alkenals, Strecker aldehydes, dialdehydes, ketones and furan aldehydes) with regard to linearity, repeatability, inter and intra-day precision and accuracy, showing that the method is suitable for the determination of carbonyl compounds in Wines. Tawny Wines with ‘indication of age’ (10–40 years old) presented the highest levels of some carbonyl compounds, such as propanal, pentanal, hexanal, Strecker aldehydes, diacetyl, methyl glyoxal, 3-pentanone and 2-furfural, whereas Ruby Wines were characterized by the highest amounts of some unidentified compounds.

  • Development and optimization of a HS-SPME-GC-MS methodology to quantify volatile carbonyl compounds in Port Wines
    'Elsevier BV', 2019
    Co-Authors: Moreira Nathalie, Victor De Freitas, Araújo, Ana Margarida, Rogerson Frank, Vasconcelos Isabel, Paula Guedes De Pinho
    Abstract:

    A method based on headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-triple quadrupole/mass spectrometry detection (GC-TQ/MS) with a prior derivatization step with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was developed to quantify carbonyl compounds in different categories of Port Wines. Optimal extraction conditions were obtained incubating 2 ml of wine with 2.3 g/l of PFBHA for 10 min and extracted during 20 min at 32 °C. The method was validated for 38 carbonyl compounds (alkanals, alkenals, Strecker aldehydes, dialdehydes, ketones and furan aldehydes) with regard to linearity, repeatability, inter and intra-day precision and accuracy, showing that the method is suitable for the determination of carbonyl compounds in Wines. Tawny Wines with ‘indication of age’ (10–40 years old) presented the highest levels of some carbonyl compounds, such as propanal, pentanal, hexanal, Strecker aldehydes, diacetyl, methyl glyoxal, 3-pentanone and 2-furfural, whereas Ruby Wines were characterized by the highest amounts of some unidentified compounds.info:eu-repo/semantics/publishedVersio

  • Simultaneous determination of ketoacids and dicarbonyl compounds, key Maillard intermediates on the generation of aged wine aroma.
    Journal of Food Science, 2007
    Co-Authors: Antonio Cesar Silva Ferreira, Carla Oliveira, Sofia Reis, César Rodrigues, Paula Guedes De Pinho
    Abstract:

    :  The aim of this work was the simultaneous determination of both ketoacids and dicarbonyl compounds in wine. To detect ketoacid compounds in wine, a method based on the quinoxaline derivatives by the reaction with diaminobenzene, currently employed to detect α-dicarbonyl compounds, was developed. The quinoxaline derivatives were detected by RP-HPLC with UV detection, which allows the determination of the major dicarbonyl compounds in wine: glyoxal, methylglyoxal, diacetyl and pentane-2,6-dione, and the quinoxaline/quinoxalinol derivatives of α-keto-γ-(methylthio)butyric acid and β-phenylpyruvic acid (intermediate ketoacid compounds of methional and phenylacetaldehyde) were simultaneously detected by a fluorescence detector. The identification was performed by comparison with standards and also by using LC-MSMS. The levels found in 15 Wines analyzed (white Wines, Madeira Wines, and Port Wines) diverge according to the type and the age of the wine. The ketoacid compounds ranged from 0.2 to 5.7 mg/L for α-keto-γ-(methylthio)butyric acid and 0.1 to 9.6 mg/L for β-phenylpyruvic acid. The quantities observed for dicarbonyl compounds were similar to those already rePorted.

  • Nor-isoprenoids profile during Port wine ageing—influence of some technological parameters
    'Elsevier BV', 2004
    Co-Authors: Ferreira, António César Silva, Paula Guedes De Pinho
    Abstract:

    Nor-isoprenoid compounds, such as β-damascenone, β-ionone, 2,2,6-trimethylcyclohexanone (TCH), 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) and vitispirane were determined in 14 young Port Wines and 45 old Port Wines. As between the two groups of Wines levels of these compounds are quite different, an experimental protocol was performed in order to determine which technological parameter (dissolved O2, free SO2 levels, pH and time/temperature) was related with the formation/consumption of these molecules. The five nor-isoprenoids were equally affected by the selected parameters and a similar profile with time was observed. The synergistic effects of increasing temperature and lowering pH had the largest impact. For samples treated with high oxygen regimes (saturation), the levels of all considered nor-isoprenoids decreased after a certain concentration of oxygen consumed (e.g. 10 mg l−1). Nevertheless, during barrel Port wine ageing, corresponding to the 45 Wines, two different behaviours can be observed: TDN, vitispirane and TCH increase significantly whilst a decrease of levels of β-ionone and β-damascenone with Port barrel ageing was observed. It was also calculated that “over 40 year” old Port Wines have, respectively, 15, 5 and 3 times higher levels of TDN, vitispirane and TCH than the young Ports. For these three compounds the respective rates of formation are higher than those of degradation, which suggests a higher number or higher concentration of precursors than those involved for the megastigame C13 nor-isoprenoids β-damascenone and β-ionone

  • influence of some technological parameters on the formation of dimethyl sulfide 2 mercaptoethanol methionol and dimethyl sulfone in Port Wines
    Journal of Agricultural and Food Chemistry, 2003
    Co-Authors: Antonio Cesar Silva Ferreira, P Rodrigues, Tim Hogg, Paula Guedes De Pinho
    Abstract:

    Volatile sulfur compounds of 15 young Port Wines and 12 old Port Wines were determined. As there is a great difference in the pool of sulfur compounds between the two groups of Wines, an experimental protocol was performed to determine which technological parameter (dissolved O(2), free SO(2) levels, pH, and time/temperature) was related with the formation/consumption of these compounds. Four sulfur compounds were selected for this purpose: dimethyl sulfide, 2-mercaptoethanol, dimethyl sulfone, and methionol. The synergistic effects of increasing temperature and O(2) at lower pH had the largest impact. Dimethyl sulfide was formed during the experimental period in the presence of O(2). Dimethyl sulfone had the same behavior. Methionol decreased significantly in the presence of O(2), but no methional was formed. 2-Mercaptoethanol, considered to be an imPortant "off-flavor" in dry Wines, also decreased during the experimental period (54 days) in the presence of O(2), and the respective disulfide was formed. These results corroborate the fact that old Port wine (barrel aged) never develops "off-flavors" associated with the presence of methionol (cauliflower), 2-mercaptoethanol (rubber/burnt), or methional (cooked potato). In fact, temperature and oxygen are the major factors in the consumption of these molecules. However, some notes of "quince" and "metallic" can appear during Port wine aging, and these can be associated with the presence of dimethyl sulfide.

Antonio Cesar Silva Ferreira - One of the best experts on this subject based on the ideXlab platform.

  • quantification of 3 deoxyglucosone 3dg as an aging marker in natural and forced aged Wines
    Journal of Food Composition and Analysis, 2016
    Co-Authors: Carla Oliveira, António Jorge Silvestre, António S. Barros, Antonio Cesar Silva Ferreira, Sónia A.o. Santos, Artur M S Silva
    Abstract:

    Abstract The Maillard reaction product 3-deoxyglucosone (3DG) was quantified in Wines, by high-performance liquid chromatography-mass spectrometry analysis after derivatization with ortho-phenylenediamine. Both sweet red Port Wines and dry white Wines were analysed during natural and forced aging. In natural aging, and for dry white Wines, 3DG is negatively correlated to age (r = −0.939), while for sweet red Port Wines, 3DG is positively correlated to age (r = 0.782). The same tendency was observed during a wine forced aging protocol. For a dry white wine, with higher levels of α-amino acids, 3DG is consumed (kconsumption 0.077–0.098 day−1) along the time protocol, while for a sweet red Port wine, with lower levels of α-amino acids, an accumulation of 3DG is observed with time (kformation 0.041–0.060 day−1). These results suggest that 3DG content can be used as an aging marker, as it has discriminated dry white and sweet red Port Wines from different ages and cultivars. Analysis of wine-model solutions allowed verifying that the fructose content has a higher effect on 3DG formation than glucose, as well as that an increase on amino acids content does not lead to an increase of 3DG yields.

  • Simultaneous determination of ketoacids and dicarbonyl compounds, key Maillard intermediates on the generation of aged wine aroma.
    Journal of Food Science, 2007
    Co-Authors: Antonio Cesar Silva Ferreira, Carla Oliveira, Sofia Reis, César Rodrigues, Paula Guedes De Pinho
    Abstract:

    :  The aim of this work was the simultaneous determination of both ketoacids and dicarbonyl compounds in wine. To detect ketoacid compounds in wine, a method based on the quinoxaline derivatives by the reaction with diaminobenzene, currently employed to detect α-dicarbonyl compounds, was developed. The quinoxaline derivatives were detected by RP-HPLC with UV detection, which allows the determination of the major dicarbonyl compounds in wine: glyoxal, methylglyoxal, diacetyl and pentane-2,6-dione, and the quinoxaline/quinoxalinol derivatives of α-keto-γ-(methylthio)butyric acid and β-phenylpyruvic acid (intermediate ketoacid compounds of methional and phenylacetaldehyde) were simultaneously detected by a fluorescence detector. The identification was performed by comparison with standards and also by using LC-MSMS. The levels found in 15 Wines analyzed (white Wines, Madeira Wines, and Port Wines) diverge according to the type and the age of the wine. The ketoacid compounds ranged from 0.2 to 5.7 mg/L for α-keto-γ-(methylthio)butyric acid and 0.1 to 9.6 mg/L for β-phenylpyruvic acid. The quantities observed for dicarbonyl compounds were similar to those already rePorted.

  • influence of some technological parameters on the formation of dimethyl sulfide 2 mercaptoethanol methionol and dimethyl sulfone in Port Wines
    Journal of Agricultural and Food Chemistry, 2003
    Co-Authors: Antonio Cesar Silva Ferreira, P Rodrigues, Tim Hogg, Paula Guedes De Pinho
    Abstract:

    Volatile sulfur compounds of 15 young Port Wines and 12 old Port Wines were determined. As there is a great difference in the pool of sulfur compounds between the two groups of Wines, an experimental protocol was performed to determine which technological parameter (dissolved O(2), free SO(2) levels, pH, and time/temperature) was related with the formation/consumption of these compounds. Four sulfur compounds were selected for this purpose: dimethyl sulfide, 2-mercaptoethanol, dimethyl sulfone, and methionol. The synergistic effects of increasing temperature and O(2) at lower pH had the largest impact. Dimethyl sulfide was formed during the experimental period in the presence of O(2). Dimethyl sulfone had the same behavior. Methionol decreased significantly in the presence of O(2), but no methional was formed. 2-Mercaptoethanol, considered to be an imPortant "off-flavor" in dry Wines, also decreased during the experimental period (54 days) in the presence of O(2), and the respective disulfide was formed. These results corroborate the fact that old Port wine (barrel aged) never develops "off-flavors" associated with the presence of methionol (cauliflower), 2-mercaptoethanol (rubber/burnt), or methional (cooked potato). In fact, temperature and oxygen are the major factors in the consumption of these molecules. However, some notes of "quince" and "metallic" can appear during Port wine aging, and these can be associated with the presence of dimethyl sulfide.

  • influence of some technological parameters on the formation of dimethyl sulfide 2 mercaptoethanol methionol and dimethyl sulfone in Port Wines
    Journal of Agricultural and Food Chemistry, 2003
    Co-Authors: Antonio Cesar Silva Ferreira, P Rodrigues, Tim Hogg, Paula Guedes De Pinho
    Abstract:

    Volatile sulfur compounds of 15 young Port Wines and 12 old Port Wines were determined. As there is a great difference in the pool of sulfur compounds between the two groups of Wines, an experiment...

Jose O Fernandes - One of the best experts on this subject based on the ideXlab platform.

  • gas chromatography mass spectrometry assessment of amines in Port wine and grape juice after fast chloroformate extraction derivatization
    Journal of Agricultural and Food Chemistry, 2011
    Co-Authors: Sara C Cunha, Miguel A Faria, Jose O Fernandes
    Abstract:

    A simple, reliable, and sensitive gas chromatography–mass spectrometry method for the quantification of volatile and nonvolatile biogenic amines in Port Wines and grape juices was developed and eva...

  • gas chromatography mass spectrometry assessment of amines in Port wine and grape juice after fast chloroformate extraction derivatization
    Journal of Agricultural and Food Chemistry, 2011
    Co-Authors: Sara C Cunha, Miguel A Faria, Jose O Fernandes
    Abstract:

    A simple, reliable, and sensitive gas chromatography-mass spectrometry method for the quantification of volatile and nonvolatile biogenic amines in Port Wines and grape juices was developed and evaluated. The method was based on a previously rePorted two-phase derivatization procedure with isobutyl chloroformate in a toluene medium, which provides a quantitative reaction in 10 min. Following the derivatization step, the excess of reagent was eliminated by treatment with alkaline methanol. The derivatization procedure was performed directly on 1 mL of sample, avoiding any fastidious and time-consuming cleanup extraction steps. The method allows the simultaneous quantification of 22 amines, which can be found in Wines: methylamine, dimethylamine, ethylamine, diethylamine, propylamine, isopropylamine, butylamine, isobutylamine, amylamine, isoamylamine, 2-methylbutylamine, hexylamine, pyrrolidine, piperidine, morpholine, 1,3-diaminopropane, putrescine, cadaverine, 1,6-diaminohexane, 2-phenylethylamine, histamine, and tyramine. Because of the fact that histamine and tyramine derivatives are degraded during the isobutyl chloroformate elimination step, the corresponding determination was made after removal of the excess of derivatizing reagent by evaporating an aliquot of the toluene layer obtained after the reaction. The presented method showed excellent analytical characteristics in what linearity, recovery, repeatability, and limit of detections were respected. It was used to assess the concentration of biogenic amines in juice grapes and Tawny and Vintage Port Wines with different aging times. On the whole, the total content of amines in Port Wines was low. Most of the amines found in Wines have their origin in the raw material used for their elaboration, so the Port winemaking process is not prone to the production of this kind of compounds. Total biogenic amine contents have shown a decrease with the aging of both types of Port Wines.

  • combined ion pair extraction and gas chromatography mass spectrometry for the simultaneous determination of diamines polyamines and aromatic amines in Port wine and grape juice
    Journal of Chromatography A, 2000
    Co-Authors: Jose O Fernandes, Margarida A Ferreira
    Abstract:

    An accurate and very sensitive method which allows for the simultaneous determination of the diamines (1,3-diaminopropane, putrescine and cadaverine), of the polyamines (spermidine and spermine), and of the aromatic amines (beta-phenylethylamine and tyramine) found in Port Wines and corresponding grape juices is presented. Sample clean-up consisted of the extraction of the amines with the ion-pairing reagent bis-2-ethylhexylphosphate dissolved in chloroform followed by a back-extraction with 0.1 M HCl. The hydrochloric extract obtained was dried and the amines were further derivatized with heptafluorobutyric anhydride and analyzed by GC-MS in the selected ion-monitoring mode, with a total run time of 18 min. Under the adopted conditions, the extraction of all the studied compounds was almost complete and the obtained extracts were free of potential interferents present in the samples, namely sugars, and most of the amino acids and polyphenols. Via the use of a set of five selected internal standards (amphetamine, [2H8]putrescine, 1,7-diaminoheptane, norspermidine and norspermine), the data obtained from the linearity, repeatability and recovery experiments were very good for all the compounds assayed. The corresponding limits of detection were invariably below 10 microg l(-1). The method was successfully applied to measure the content of biogenic amines in twelve young and five aged Port wine samples, eleven grape juice samples as well as in ten Portuguese red and white table Wines. Results are presented and briefly discussed.

  • combined ion pair extraction and gas chromatography mass spectrometry for the simultaneous determination of diamines polyamines and aromatic amines in Port wine and grape juice
    Journal of Chromatography A, 2000
    Co-Authors: Jose O Fernandes, Margarida A Ferreira
    Abstract:

    An accurate and very sensitive method which allows for the simultaneous determination of the diamines (1,3-diaminopropane, putrescine and cadaverine), of the polyamines (spermidine and spermine), and of the aromatic amines (β-phenylethylamine and tyramine) found in Port Wines and corresponding grape juices is presented. Sample clean-up consisted of the extraction of the amines with the ion-pairing reagent bis-2-ethylhexylphosphate dissolved in chloroform followed by a back-extraction with 0.1 M HCl. The hydrochloric extract obtained was dried and the amines were further derivatized with heptafluorobutyric anhydride and analyzed by GC–MS in the selected ion-monitoring mode, with a total run time of 18 min. Under the adopted conditions, the extraction of all the studied compounds was almost complete and the obtained extracts were free of potential interferents present in the samples, namely sugars, and most of the aminoacids and polyphenols. Via the use of a set of five selected internal standards (amphetamine, [2H8]putrescine, 1,7-diaminoheptane, norspermidine and norspermine), the data obtained from the linearity, repeatability and recovery experiments were very good for all the compounds assayed. The corresponding limits of detection were invariably below 10 μg l−1. The method was successfully applied to measure the content of biogenic amines in twelve young and five aged Port wine samples, eleven grape juice samples as well as in ten Portuguese red and white table Wines. Results are presented and briefly discussed.

Artur M S Silva - One of the best experts on this subject based on the ideXlab platform.

  • quantification of 3 deoxyglucosone 3dg as an aging marker in natural and forced aged Wines
    Journal of Food Composition and Analysis, 2016
    Co-Authors: Carla Oliveira, António Jorge Silvestre, António S. Barros, Antonio Cesar Silva Ferreira, Sónia A.o. Santos, Artur M S Silva
    Abstract:

    Abstract The Maillard reaction product 3-deoxyglucosone (3DG) was quantified in Wines, by high-performance liquid chromatography-mass spectrometry analysis after derivatization with ortho-phenylenediamine. Both sweet red Port Wines and dry white Wines were analysed during natural and forced aging. In natural aging, and for dry white Wines, 3DG is negatively correlated to age (r = −0.939), while for sweet red Port Wines, 3DG is positively correlated to age (r = 0.782). The same tendency was observed during a wine forced aging protocol. For a dry white wine, with higher levels of α-amino acids, 3DG is consumed (kconsumption 0.077–0.098 day−1) along the time protocol, while for a sweet red Port wine, with lower levels of α-amino acids, an accumulation of 3DG is observed with time (kformation 0.041–0.060 day−1). These results suggest that 3DG content can be used as an aging marker, as it has discriminated dry white and sweet red Port Wines from different ages and cultivars. Analysis of wine-model solutions allowed verifying that the fructose content has a higher effect on 3DG formation than glucose, as well as that an increase on amino acids content does not lead to an increase of 3DG yields.

  • pyranoanthocyanin dimers a new family of turquoise blue anthocyanin derived pigments found in Port wine
    Journal of Agricultural and Food Chemistry, 2010
    Co-Authors: Joana Oliveira, Nuno Mateus, Artur M S Silva, Joana Azevedo, Luis Cruz, Natercia Teixeira, Victor De Freitas
    Abstract:

    In the present work, several compounds bearing similar spectroscopic features were found to occur in aged Port Wines and respective sediments (lees). The data obtained revealed two new families of compounds with unique spectroscopic characteristics, displaying a wavelength of the maximum absorption at high wavelength in the visible spectrum at ∼730 and ∼680 nm. The structure of these pigments was elucidated by liquid chromatography/diode array detector−mass spectrometry (LC/DAD−MS) and nuclear magnetic resonance (NMR), and their formation pathway in Wines was established. Their structure is constituted by two pyranoanthocyanin moieties linked together through a methyne bridge. This new family of compounds displays an attractive and rare turquoise blue color at acidic conditions and has never been rePorted in the literature.

P Rodrigues - One of the best experts on this subject based on the ideXlab platform.

  • RESULTS AND DISCUSSION
    2016
    Co-Authors: A Silva C Ferreira, P Rodrigues, Guedes P. De ,pinho, C. Lopes, T. Hogg, Escola Superior De Biotecnologia, Universidade Catolica Portuguesa
    Abstract:

    The “oxidative degradation ” of white Wines rapidly leads to a loss of their sensorial qualities. The presence of “off-flavours ” has been attributed to compounds such as methional, eugenol, sotolon and 2,3,5-trimethyl-1,3-dioxolane (1). It has been shown that cyclic acetals are closely related to the progressive formation of ethanal and sotolon, during “oxidative aging ” of Port Wines (2), the. 1,1,6-trimethyl-1,2-dihydronaphtalene(TDN), a substance responsible for the “kerosene ” aromas typical of old Wines from the Riesling variety has been rePorted as increasing in concentration during “accelerated ” oxidation (3). In the present study sniffing analysis is employed to screen for the presence of aromatic zones with odors related with descriptors characteristic of “precocious aging”. The “Aroma Extract Dilution Analysis”technique (4), has been used, with great success in the identification of the substances responsible for the typical aromas of various foodstuffs (5,6). Therefore the application of this procedure to both normal and to spoiled white Wines permits the comparison of the respective aromograms enabling the selection of the substances of greatest interest for identification as responsible for undesirable aromas in study

  • influence of some technological parameters on the formation of dimethyl sulfide 2 mercaptoethanol methionol and dimethyl sulfone in Port Wines
    Journal of Agricultural and Food Chemistry, 2003
    Co-Authors: Antonio Cesar Silva Ferreira, P Rodrigues, Tim Hogg, Paula Guedes De Pinho
    Abstract:

    Volatile sulfur compounds of 15 young Port Wines and 12 old Port Wines were determined. As there is a great difference in the pool of sulfur compounds between the two groups of Wines, an experimental protocol was performed to determine which technological parameter (dissolved O(2), free SO(2) levels, pH, and time/temperature) was related with the formation/consumption of these compounds. Four sulfur compounds were selected for this purpose: dimethyl sulfide, 2-mercaptoethanol, dimethyl sulfone, and methionol. The synergistic effects of increasing temperature and O(2) at lower pH had the largest impact. Dimethyl sulfide was formed during the experimental period in the presence of O(2). Dimethyl sulfone had the same behavior. Methionol decreased significantly in the presence of O(2), but no methional was formed. 2-Mercaptoethanol, considered to be an imPortant "off-flavor" in dry Wines, also decreased during the experimental period (54 days) in the presence of O(2), and the respective disulfide was formed. These results corroborate the fact that old Port wine (barrel aged) never develops "off-flavors" associated with the presence of methionol (cauliflower), 2-mercaptoethanol (rubber/burnt), or methional (cooked potato). In fact, temperature and oxygen are the major factors in the consumption of these molecules. However, some notes of "quince" and "metallic" can appear during Port wine aging, and these can be associated with the presence of dimethyl sulfide.

  • influence of some technological parameters on the formation of dimethyl sulfide 2 mercaptoethanol methionol and dimethyl sulfone in Port Wines
    Journal of Agricultural and Food Chemistry, 2003
    Co-Authors: Antonio Cesar Silva Ferreira, P Rodrigues, Tim Hogg, Paula Guedes De Pinho
    Abstract:

    Volatile sulfur compounds of 15 young Port Wines and 12 old Port Wines were determined. As there is a great difference in the pool of sulfur compounds between the two groups of Wines, an experiment...