The Experts below are selected from a list of 561 Experts worldwide ranked by ideXlab platform

José C. Marques - One of the best experts on this subject based on the ideXlab platform.

  • Rapid Determination of Sotolon in Fortified Wines Using a Miniaturized Liquid-Liquid Extraction Followed by LC-MS/MS Analysis
    Journal of analytical methods in chemistry, 2018
    Co-Authors: Vanda Pereira, Joao M Gaspar, Joao M Leca, Ana C. Pereira, José C. Marques
    Abstract:

    Sotolon (4,5-dimethyl-3-hydroxy-2,5-dihydrofuran-2-one) is a powerful odorant usually pointed out as being responsible not only for the characteristic curry notes of the finest Fortified Wines but also for the off-flavour notes in prematurely oxidized white Wines. Most methods reported in literature for quantifying sotolon in Wines are quite laborious and use large volumes of organic solvents. Thus, in the present study, the development of a simple, fast, and environment-friendly method for the quantification of sotolon in Fortified wine is herein presented. The proposed method uses a single-step liquid-liquid extraction followed by RP-LC-MS/MS and was optimized using a full factorial design. The method showed good linearity (R2 = 0.9999), intra- and interday precision lower than 10% RSD, recovery of about 95%, and high sensitivity (LOQ of 0.04 μg/L). The method was applied to analyse 44 Fortified Wines from different styles (from dry to sweet Wines) and ages (3–115 years old), and it was found that it covers the concentration range usually found for this compound in this kind of alcoholic beverages, which was found to be within 6.3–810 μg/L. Thus, it can be concluded that this method can be used as an accurate tool for the rapid analysis of sotolon, since the early stages of its formation up to long ageing periods.

  • Amino Acids and Biogenic Amines Evolution during the Estufagem of Fortified Wines
    Journal of Chemistry, 2015
    Co-Authors: Vanda Pereira, Ana C. Pereira, Juan Pedro Pérez Trujillo, Juan Cacho, José C. Marques
    Abstract:

    The current study was focused on the impact of accelerated ageing (heating step) on the amino acid and biogenic amine profiles of Fortified Wines. In this sense, three Madeira Wines from two commonly used grape varieties (one red and the other white) were analysed during the heating, at standard (45°C, 3 months) and overheating (70°C, 1 month) conditions, following a precolumn derivatization procedure using iodoacetic acid, o-phthaldialdehyde, and 2-mercaptoethanol, carried out in the injection loop prior to RP-HPLC-FLD detection. Eighteen amino acids were identified, with arginine being the most abundant. An important decrease of the amino acid levels was detected during the standard heating (up to 30%), enhanced up to 61% by the temperature increase. Cysteine, histidine, and asparagine revealed the greatest decreases at 45°C. Conversely, some amino acids, such as asparagine, slightly increased. Four biogenic amines were identified but always in trace amounts. Finally, it was observed that the accelerated ageing did not favour the biogenic amine development. The results also indicate that the heating process promotes the amino acid transformation into new ageing products.

  • Rapid and sensitive methodology for determination of ethyl carbamate in Fortified Wines using microextraction by packed sorbent and gas chromatography with mass spectrometric detection.
    Analytica chimica acta, 2013
    Co-Authors: Joao M Leca, Vanda Pereira, Ana C. Pereira, José C. Marques
    Abstract:

    Abstract This work presents a new methodology to quantify ethyl carbamate (EC) in Fortified Wines. The presented approach combines the microextraction by packed sorbent (MEPS), using a hand-held automated analytical syringe, with one-dimensional gas chromatography coupled with mass spectrometry detection (GC–MS). The performance of different MEPS sorbent materials was tested, namely SIL, C2, C8, C18, and M1. Also, several extraction solvents and the matrix effect were evaluated. Experimental data showed that C8 and dichloromethane were the best sorbent/solvent pair to extract EC. Concerning solvent and sample volumes optimization used in MEPS extraction an experimental design (DoE) was carried out. The best extraction yield was achieved passing 300 μL of sample and 100 μL of dichloromethane. The method validation was performed using a matrix-matched calibration using both sweet and dry Fortified Wines, to minimize the matrix effect. The proposed methodology presented good linearity (R2 = 0.9999) and high sensitivity, with quite low limits of detection (LOD) and quantification (LOQ), 1.5 μg L−1 and 4.5 μg L−1, respectively. The recoveries varied between 97% and 106%, while the method precision (repeatability and reproducibility) was lower than 7%. The applicability of the methodology was confirmed through the analysis of 16 Fortified Wines, with values ranging between 7.3 and 206 μg L−1. All chromatograms showed good peak resolution, confirming its selectivity. The developed MEPS/GC–MS methodology arises as an important tool to quantify EC in Fortified Wines, combining efficiency and effectiveness, with simpler, faster and affordable analytical procedures that provide great sensitivity without using sophisticated and expensive equipment.

  • Polyphenols, Antioxidant Potential and Color of Fortified Wines during Accelerated Ageing: The Madeira Wine Case Study
    Molecules (Basel Switzerland), 2013
    Co-Authors: Vanda Pereira, Francisco Albuquerque, Juan Cacho, José C. Marques
    Abstract:

    Polyphenols, antioxidant potential and color of three types of Fortified Madeira Wines were evaluated during the accelerated ageing, named as estufagem. The traditional estufagem process was set to 45 °C for 3 months. Overheating conditions, 1 month at 70 °C, were also examined. Total polyphenols (TP), total monomeric anthocyanins (TMA) and total flavonoids (TF) were assessed by spectrophotometric methods, while individual polyphenols and furans were simultaneously determined by HPLC-DAD. Antioxidant potential (AP) was estimated by ABTS, DPPH and FRAP assays, while color was evaluated by Glories and CIELab. Traditional estufagem decreased the TP and AP up to 20% and 26%, respectively, with final values similar to other Wines. TMA of the Madeira Wines from red grapes decreased during estufagem. Six hydroxybenzoic acids, three hydroxycinnamic acids, one stilbene, three flavonols and three flavan-3-ols were found in these Wines. The prominent phenolics were hydroxycinnamates and hydroxybenzoates, even after estufagem. Most polyphenols decreased, with the exception of caffeic, ferulic, p-coumaric, gallic and syringic acids. Finally, both chromatic systems revealed that all Wines tended to similar chromatic characteristics after estufagem. The study suggests that estufagem can be applied without high impact on polyphenols and antioxidant potential of these Fortified Wines.

  • Evolution of 5-hydroxymethylfurfural (HMF) and furfural (F) in Fortified Wines submitted to overheating conditions
    Food Research International, 2011
    Co-Authors: Vanda Pereira, Juan Cacho, F.m. Albuquerque, António César Silva Ferreira, José C. Marques
    Abstract:

    Abstract As furfural (F) and 5-hydroxymethylfurfural (HMF) are essentially formed from sugar dehydration, especially in food submitted to heat, they can be found in beverages, as well as Fortified sweet Wines. In order to assess the impact of temperature on Madeira winemaking, three traditional varieties of Madeira Wines (Malvasia, Sercial and Tinta Negra Mole) were studied to evaluate the F and HMF contents. The Wines were produced by two vinification processes, following traditional and modern methodologies, heated at standard conditions (30 °C and 45 °C, for 4 months) and compared with the same Wines submitted to overheating conditions (55 °C, for 4 months). The RP-HPLC-DAD methodology used for the control of F and HMF during the process showed no significant changes in the Wines maintained at 30 °C (canteiro) and a noticeable but controlled increase in the Wines heated at 45 °C (estufagem) where values up to about 150 mg/L of HMF could be found in sweet Wines. The strong relation of this compound with the sugar content and baking temperature stood out in the Wines submitted to overheating conditions where values higher than 1 g/L could be found for sweeter Wines, with HMF level being in general higher than F. The results clearly suggest that the amount of HMF in these Fortified Wines can be easily controlled when submitted to adequate conditions of heating during estufagem and storage. Furthermore, different temperatures for the baking of sweet and dry Wines may be considered.

Vanda Pereira - One of the best experts on this subject based on the ideXlab platform.

  • Rapid Determination of Sotolon in Fortified Wines Using a Miniaturized Liquid-Liquid Extraction Followed by LC-MS/MS Analysis
    Journal of analytical methods in chemistry, 2018
    Co-Authors: Vanda Pereira, Joao M Gaspar, Joao M Leca, Ana C. Pereira, José C. Marques
    Abstract:

    Sotolon (4,5-dimethyl-3-hydroxy-2,5-dihydrofuran-2-one) is a powerful odorant usually pointed out as being responsible not only for the characteristic curry notes of the finest Fortified Wines but also for the off-flavour notes in prematurely oxidized white Wines. Most methods reported in literature for quantifying sotolon in Wines are quite laborious and use large volumes of organic solvents. Thus, in the present study, the development of a simple, fast, and environment-friendly method for the quantification of sotolon in Fortified wine is herein presented. The proposed method uses a single-step liquid-liquid extraction followed by RP-LC-MS/MS and was optimized using a full factorial design. The method showed good linearity (R2 = 0.9999), intra- and interday precision lower than 10% RSD, recovery of about 95%, and high sensitivity (LOQ of 0.04 μg/L). The method was applied to analyse 44 Fortified Wines from different styles (from dry to sweet Wines) and ages (3–115 years old), and it was found that it covers the concentration range usually found for this compound in this kind of alcoholic beverages, which was found to be within 6.3–810 μg/L. Thus, it can be concluded that this method can be used as an accurate tool for the rapid analysis of sotolon, since the early stages of its formation up to long ageing periods.

  • odor detection threshold odt and odor rejection threshold ort determination of sotolon in madeira wine a preliminary study
    agriculture 2018 Vol. 3 Pages 172-180, 2018
    Co-Authors: Joao M Gaspar, Vanda Pereira, And Jose C Marques
    Abstract:

    Madeira is a Fortified wine, well renowned worldwide. It is during the aging process that its characteristic bouquet is developed, through the formation of specific aromas. Sotolon (3-hydroxy-4,5-dimethyl-2(5 H )-furanone) is frequently pointed out as one of the molecules responsible for the aroma of the finest Madeiras. The present work serves as a preliminary insight on the sensorial impact of this compound in Madeira wine. The odor detection threshold of sotolon in a sweet-type Madeira was obtained by the 3-Alternative Forced Choice method. The estimated threshold value was obtained by 19 non-trained and non-expert panelists, within the spiked range 4–314 µg/L. An odor threshold of 112 µg/L was obtained using a 3-year-old Madeira with 6.3 ± 0.4 µg/L endogenous sotolon. This result is about 6-fold higher than those previously reported for other Fortified Wines. A Paired Preference test was chosen to determine the concentration at which the panelists would reject the wine spiked with sotolon. Nineteen panelists assessed a series of spiked concentrations ranging from 253–3464 µg/L. Within this range, it is not possible to define the concentration value from which the aroma of sotolon it is no longer pleasant. Thus, an odor rejection threshold could not be obtained. Indeed, the study also suggests that sotolon does not become unpleasant at higher concentrations.

  • Amino Acids and Biogenic Amines Evolution during the Estufagem of Fortified Wines
    Journal of Chemistry, 2015
    Co-Authors: Vanda Pereira, Ana C. Pereira, Juan Pedro Pérez Trujillo, Juan Cacho, José C. Marques
    Abstract:

    The current study was focused on the impact of accelerated ageing (heating step) on the amino acid and biogenic amine profiles of Fortified Wines. In this sense, three Madeira Wines from two commonly used grape varieties (one red and the other white) were analysed during the heating, at standard (45°C, 3 months) and overheating (70°C, 1 month) conditions, following a precolumn derivatization procedure using iodoacetic acid, o-phthaldialdehyde, and 2-mercaptoethanol, carried out in the injection loop prior to RP-HPLC-FLD detection. Eighteen amino acids were identified, with arginine being the most abundant. An important decrease of the amino acid levels was detected during the standard heating (up to 30%), enhanced up to 61% by the temperature increase. Cysteine, histidine, and asparagine revealed the greatest decreases at 45°C. Conversely, some amino acids, such as asparagine, slightly increased. Four biogenic amines were identified but always in trace amounts. Finally, it was observed that the accelerated ageing did not favour the biogenic amine development. The results also indicate that the heating process promotes the amino acid transformation into new ageing products.

  • Rapid and sensitive methodology for determination of ethyl carbamate in Fortified Wines using microextraction by packed sorbent and gas chromatography with mass spectrometric detection.
    Analytica chimica acta, 2013
    Co-Authors: Joao M Leca, Vanda Pereira, Ana C. Pereira, José C. Marques
    Abstract:

    Abstract This work presents a new methodology to quantify ethyl carbamate (EC) in Fortified Wines. The presented approach combines the microextraction by packed sorbent (MEPS), using a hand-held automated analytical syringe, with one-dimensional gas chromatography coupled with mass spectrometry detection (GC–MS). The performance of different MEPS sorbent materials was tested, namely SIL, C2, C8, C18, and M1. Also, several extraction solvents and the matrix effect were evaluated. Experimental data showed that C8 and dichloromethane were the best sorbent/solvent pair to extract EC. Concerning solvent and sample volumes optimization used in MEPS extraction an experimental design (DoE) was carried out. The best extraction yield was achieved passing 300 μL of sample and 100 μL of dichloromethane. The method validation was performed using a matrix-matched calibration using both sweet and dry Fortified Wines, to minimize the matrix effect. The proposed methodology presented good linearity (R2 = 0.9999) and high sensitivity, with quite low limits of detection (LOD) and quantification (LOQ), 1.5 μg L−1 and 4.5 μg L−1, respectively. The recoveries varied between 97% and 106%, while the method precision (repeatability and reproducibility) was lower than 7%. The applicability of the methodology was confirmed through the analysis of 16 Fortified Wines, with values ranging between 7.3 and 206 μg L−1. All chromatograms showed good peak resolution, confirming its selectivity. The developed MEPS/GC–MS methodology arises as an important tool to quantify EC in Fortified Wines, combining efficiency and effectiveness, with simpler, faster and affordable analytical procedures that provide great sensitivity without using sophisticated and expensive equipment.

  • polyphenols antioxidant potential and color of Fortified Wines during accelerated ageing the madeira wine case study
    Molecules, 2013
    Co-Authors: Vanda Pereira, Francisco Albuquerque, Juan Cacho, J. C. Marques
    Abstract:

    Abstract: Polyphenols, antioxidant potential and color of three types of Fortified Madeira Wines were evaluated during the accelerated ageing, named as estufagem . The traditional estufagem process was set to 45 °C for 3 months. Overheating conditions, 1 month at 70 °C, were also examined. Total polyphenols (TP), total monomeric anthocyanins (TMA) and total flavonoids (TF) were assessed by spectrophotometric methods, while individual polyphenols and furans were simultaneously determined by HPLC-DAD. Antioxidant potential (AP) was estimated by ABTS, DPPH and FRAP assays, while color was evaluated by Glories and CIELab. Traditional e stufagem decreased the TP and AP up to 20% and 26%, respectively, with final values similar to other Wines. TMA of the Madeira Wines from red grapes decreased during estufagem . Six hydroxybenzoic acids, three hydroxycinnamic acids, one stilbene, three flavonols and three flavan-3-ols were found in these Wines. The prominent phenolics were hydroxycinnamates and hydroxybenzoates, even after

Cristina Delerue-matos - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of six fungicides and one acaricide in still and Fortified Wines using solid-phase microextraction-gas chromatography/tandem mass spectrometry.
    Food chemistry, 2011
    Co-Authors: Joana Martins, Cristina Esteves, Tomás Simões, Manuela Correia, Ana Limpo-faria, Paulo Sergio De Moraes Barros, Natália Ribeiro, Cristina Delerue-matos
    Abstract:

    A multiresidue gas chromatographic method for the determination of six fungicides (captan, chlorthalonil, folpet, iprodione, procymidone and vinclozolin) and one acaricide (dicofol) in still and Fortified Wines was developed. Solid-phase microextraction (SPME) was chosen for the extraction of the compounds from the studied matrices and tandem mass spectrometry (MS/MS) detection was used. The extraction consists in a solvent free and automated procedure and the detection is highly sensitive and selective. Good linearity was obtained with correlation coefficients of regression (R(2))>0.99 for all the compounds. Satisfactory results of repeatability and intermediate precision were obtained for most of the analytes (RSD⩽20%). Recoveries from spiked wine ranged from 80.1% to 112.0%. Limits of quantification (LOQs) were considerably below the proposed maximum residue limits (MRLs) for these compounds in grapes and below the suggested limits for wine (MRLs/10), with the exception of captan.

  • Determination of 24 pesticide residues in Fortified Wines by solid-phase microextraction and gas chromatography-tandem mass spectrometry.
    Journal of agricultural and food chemistry, 2011
    Co-Authors: Joana Martins, Cristina Esteves, Tomás Simões, Manuela Correia, Cristina Delerue-matos
    Abstract:

    The present work describes a solid-phase microextraction (SPME) gas chromatography-tandem mass spectrometry (MS/MS) method to quantify 24 pesticides in Fortified white wine and Fortified red wine. In this study "Fortified wine" refers to a wine in which fermentation is arrested before completion by alcohol distillate addition, allowing sugar and alcoholic contents to be higher (around 80-100 g/L total sugars and 19-22% alcohol strength (v/v)). The analytical method showed good linearity, presenting correlation coefficients (R(2)) ≥ 0.989 for all compounds. Limits of detection (LOD) and quantitation (LOQ) in the ranges of 0.05-72.35 and 0.16-219.23 μg/L, respectively, were obtained. LOQs are below the maximum residue levels (MRL) set by European Regulation for grapes. The proposed method was applied to 17 commercial Fortified Wines. The analyzed pesticides were not detected in the Wines tested.

Marques, José C. - One of the best experts on this subject based on the ideXlab platform.

  • New insights into ethyl carbamate occurrence in Fortified Wines
    'Elsevier BV', 2021
    Co-Authors: Leça, João M., Pereira Vanda, Miranda Andreia, Vilchez, José Luis, Marques, José C.
    Abstract:

    The occurrence of ethyl carbamate (EC) in Fortified Wines was studied testing different model Wines under accelerated ageing (45 °C for 4 months and 70 °C for 1 month), to investigate the possibility of arginine (Arg) being a direct precursor of EC in Fortified Wines, comparing it with known major precursors, urea and citrulline (Cit). Wine main sugars were appraised as possible catalysts, as previously pointed out. Model Wines showed that: Arg can induce the EC formation under accelerated ageing, even without being metabolised by microorganisms; although much less reactive, Arg can play a significant role since high residual levels can occur in young Fortified Wines; glucose (Glc) and fructose (Fru) suppressed the EC formation from urea and Cit pathways, in about 11–26%. Moreover, Madeira wine samples were investigated in order to appraise the eventual contribution of the alcoholic fortification. The results revealed that this step can promote a decrease of the amount of these EC precursors up to 46%. Despite preliminary, additional information about the EC formation in Fortified Wines was obrained namely for designing new mitigation strategies, which can pass through the reduction of residual Arg.info:eu-repo/semantics/publishedVersio

  • Rapid determination of sotolon in Fortified Wines using a miniaturized liquid-liquid extraction followed by LC-MS/MS analysis
    'Hindawi Limited', 2018
    Co-Authors: Pereira Vanda, Pereira, Ana C., Leça, João M., Gaspar, João M., Marques, José C.
    Abstract:

    Sotolon (4,5-dimethyl-3-hydroxy-2,5-dihydrofuran-2-one) is a powerful odorant usually pointed out as being responsible not only for the characteristic curry notes of the finest Fortified Wines but also for the off-flavour notes in prematurely oxidized white Wines. Most methods reported in literature for quantifying sotolon in Wines are quite laborious and use large volumes of organic solvents. *us, in the present study, the development of a simple, fast, and environment-friendly method for the quantification of sotolon in Fortified wine is herein presented. *e proposed method uses a single-step liquid-liquid extraction followed by RP-LC MS/MS and was optimized using a full factorial design. *e method showed good linearity (R2 � 0.9999), intra- and interday precision lower than 10% RSD, recovery of about 95%, and high sensitivity (LOQ of 0.04 μg/L). *e method was applied to analyse 44 Fortified Wines from different styles (from dry to sweet Wines) and ages (3–115 years old), and it was found that it covers the concentration range usually found for this compound in this kind of alcoholic beverages, which was found to be within 6.3–810 μg/L. *us, it can be concluded that this method can be used as an accurate tool for the rapid analysis of sotolon, since the early stages of its formation up to long ageing periods.info:eu-repo/semantics/publishedVersio

  • A simple emulsification-assisted extraction method for the GC–MS/SIM analysis of wine markers of aging and oxidation: application for studying micro-oxygenation in Madeira Wine
    'Springer Science and Business Media LLC', 2018
    Co-Authors: Freitas Ana, Pereira Vanda, Pereira, Ana C., Leça, João M., Albuquerque Francisco, Marques, José C.
    Abstract:

    Sotolon and the heterocyclic acetals of glycerol are known as potential aging and oxidation markers in Fortified Wines such as Madeira, Port, and Sherry. Thus, determining the evolution of these compounds under different oxidative aging conditions is important for Fortified wine quality purposes. This study proposes a new methodology based on a miniaturized emulsification extraction followed by GC–MS/SIM, which was developed and optimized to follow the formation of sotolon and heterocyclic acetals in Fortified Wines that were submitted to traditional accelerated aging and micro-oxygenation. The optimization was achieved by means of a mixed-level factorial design, considering 3 factors: sample volume, extractant volume, and concentrated extract volume, by performing 19 experiments in duplicate. The extraction was optimized using 8 mL of wine sample, 5 mL of dichloromethane, concentrating the extract up to 10-fold. The method performance was evaluated for sotolon, using a matrix matched calibration between 10 and 2000 μg/L. The selectivity was confirmed through the analysis of real samples. The methodology showed good linearity (R2 = 0.999), high sensitivity (LOQ = 6.8 μg/L), recovery about 105%, and good precision (less than 8 and 9%, evaluated by the variation of intra- and inter-day measurements, respectively). This is the first methodology that revealed to be an excellent tool to simultaneously follow the formation of sotolon and heterocyclic acetals in Madeira Wines, using an inexpensive, simple, efficient, and effective experimental layout. Indeed, it was shown that traditional accelerated aging and micro-oxygenation have impact on the formation of such molecules.info:eu-repo/semantics/publishedVersio

  • Definitive screening designs and latent variable modelling for the optimization of solid phase microextraction (SPME): case study-quantification of volatile fatty acids in Wines
    'Elsevier BV', 2018
    Co-Authors: Pereira, Ana C., Leça, João M., Reis, Marco S., Rodrigues, Pedro M., Marques, José C.
    Abstract:

    In the present study, we apply the recently proposed Definitive Screening Designs (DSD) to optimize HS-SPME extraction in order to analyze volatile fatty acids (VFA) present in wine samples. This is the first attempt to apply this new class of designs to one of the most well-known and widely applied extraction techniques. The latent structure of the responses is also explored for defining the optimal extraction conditions. DSD is a new screening design with the potential to significantly reduce the number of experiments required to estimate the model pa rameters and to establish the optimum operation conditions. Therefore, there is an obvious interest in assessing the benefits of DSD in practice. In this work, this design framework is applied to the simultaneous optimization of seven extraction parameters (responses). Both qualitative and quantitative extraction parameters are considered, in order to test the flexibility of DSD designs: a two-level qualitative variable, the fiber coating, and six quanti tative variables, namely the pre-incubation time, the extraction time and temperature, the headspace/sample volume, the effect of agitation during extraction and the influence of the ethanol content (sample dilution). Optimization of analytes' chromatographic responses was carried out both individually (response by response) and altogether, by modelling the responses in the latent variable space (i.e., explicitly considering their under lying correlation structure). In the end, a consensus analysis of all perspectives was considered in the definition of the overall optimal extraction conditions for the quantification of VFA in Fortified Wines. The solution found was to use a DVB/Car/PDMS fiber, 10 mL of samples in 20 mL vial, 40 min of extraction at 40 C. The analysis also revealed that the factors incubation time, agitation and sample dilution do not play a significant role in explaining the variability of extraction parameters. Therefore, they were set to the most convenient levels. The methodology followed was thoroughly validated and the following figures of merit were obtained: good linearity (R2 > 0.999, for all compounds), high sensitivity (LOD and LOQ are close or below the values found in literature), recoveries of approximately 100% and suitable precision (repeatability and reproducibility lower than 7.21% and 8.61%, respectively). Finally, the optimized methodology was tested in practice. Several wine samples were analyzed and the odor activity value calculated to facilitate the identification of their importance as odor active compounds in different aged Fortified Wines. This work demonstrates the benefits of using DSD and latent variable modelling for the optimization of analytical techniques, contributing to the implementation of rigorous, systematic and more efficient optimization protocols.info:eu-repo/semantics/publishedVersio

  • Odor detection threshold (ODT) and odor rejection threshold (ORT) determination of sotolon in Madeira wine: a preliminary study
    'American Institute of Mathematical Sciences (AIMS)', 2018
    Co-Authors: Gaspar, João M., Pereira Vanda, Marques, José C.
    Abstract:

    Madeira is a Fortified wine, well renowned worldwide. It is during the aging process that its characteristic bouquet is developed, through the formation of specific aromas. Sotolon (3-hydroxy-4,5-dimethyl-2(5H)-furanone) is frequently pointed out as one of the molecules responsible for the aroma of the finest Madeiras. The present work serves as a preliminary insight on the sensorial impact of this compound in Madeira wine. The odor detection threshold of sotolon in a sweet-type Madeira was obtained by the 3-Alternative Forced Choice method. The estimated threshold value was obtained by 19 non-trained and non-expert panelists, within the spiked range 4–314 µg/L. An odor threshold of 112 µg/L was obtained using a 3-year-old Madeira with 6.3 ± 0.4 µg/L endogenous sotolon. This result is about 6-fold higher than those previously reported for other Fortified Wines. A Paired Preference test was chosen to determine the concentration at which the panelists would reject the wine spiked with sotolon. Nineteen panelists assessed a series of spiked concentrations ranging from 253–3464 µg/L. Within this range, it is not possible to define the concentration value from which the aroma of sotolon it is no longer pleasant. Thus, an odor rejection threshold could not be obtained. Indeed, the study also suggests that sotolon does not become unpleasant at higher concentrations.info:eu-repo/semantics/publishedVersio

Joana Martins - One of the best experts on this subject based on the ideXlab platform.

  • Analysis of six fungicides and one acaricide in still and Fortified Wines using solid-phase microextraction-gas chromatography/tandem mass spectrometry.
    Food chemistry, 2011
    Co-Authors: Joana Martins, Cristina Esteves, Tomás Simões, Manuela Correia, Ana Limpo-faria, Paulo Sergio De Moraes Barros, Natália Ribeiro, Cristina Delerue-matos
    Abstract:

    A multiresidue gas chromatographic method for the determination of six fungicides (captan, chlorthalonil, folpet, iprodione, procymidone and vinclozolin) and one acaricide (dicofol) in still and Fortified Wines was developed. Solid-phase microextraction (SPME) was chosen for the extraction of the compounds from the studied matrices and tandem mass spectrometry (MS/MS) detection was used. The extraction consists in a solvent free and automated procedure and the detection is highly sensitive and selective. Good linearity was obtained with correlation coefficients of regression (R(2))>0.99 for all the compounds. Satisfactory results of repeatability and intermediate precision were obtained for most of the analytes (RSD⩽20%). Recoveries from spiked wine ranged from 80.1% to 112.0%. Limits of quantification (LOQs) were considerably below the proposed maximum residue limits (MRLs) for these compounds in grapes and below the suggested limits for wine (MRLs/10), with the exception of captan.

  • Determination of 24 pesticide residues in Fortified Wines by solid-phase microextraction and gas chromatography-tandem mass spectrometry.
    Journal of agricultural and food chemistry, 2011
    Co-Authors: Joana Martins, Cristina Esteves, Tomás Simões, Manuela Correia, Cristina Delerue-matos
    Abstract:

    The present work describes a solid-phase microextraction (SPME) gas chromatography-tandem mass spectrometry (MS/MS) method to quantify 24 pesticides in Fortified white wine and Fortified red wine. In this study "Fortified wine" refers to a wine in which fermentation is arrested before completion by alcohol distillate addition, allowing sugar and alcoholic contents to be higher (around 80-100 g/L total sugars and 19-22% alcohol strength (v/v)). The analytical method showed good linearity, presenting correlation coefficients (R(2)) ≥ 0.989 for all compounds. Limits of detection (LOD) and quantitation (LOQ) in the ranges of 0.05-72.35 and 0.16-219.23 μg/L, respectively, were obtained. LOQs are below the maximum residue levels (MRL) set by European Regulation for grapes. The proposed method was applied to 17 commercial Fortified Wines. The analyzed pesticides were not detected in the Wines tested.