Barros, António S.

Oliveira, Carla Maria

Silva Ferreira, António César

Silva, Artur M. S.

English

Repositório Institucional da Universidade Católica Portuguesa

Wine oxidation profile accessed by voltammetric, antioxidantscavenging and GC-MS techniquesCarla Maria Oliveira1,2*, Artur M. S. Silva1, António S. Barros1 and António César Silva Ferreira2,31. Departamento de Química & QOPNA, Universidade de Aveiro, 3810-193 Aveiro, Portugal2. Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal3. Stellenbosch University, Private Bag X1, Matieland, 7602, Stellenbosch, South Africa* Corresponding author: cm.dias@ua.pt/ cmdias@aesbuc.ptEscola Superior de BiotecnologiaRecently, studies using cyclic voltammetric measurements enable the grouping of both quantitative and qualitative information concerning wine antioxidants(1-5). On the other hand, many aldehydes and other off-flavors, that occurs in wines, resulting from the oxidation of alcohols, sugars and amino acidsdegradations are described to have an important contribution to the sub-qualities of wine aroma and can be assessed by Gas Chromatography/Massspectrometry (GC/MS).Both target and non-target approach strategy can be used to monitor the overall reactions involved in wine oxidation. The non-target methodology includesrelevant analytical tools, in order to fuse the information of the used detectors (Cyclic voltammetry and GC/MS) allowing a most comprehensive view of thesystem and the annotation of interesting compounds.1 - Kilmartin, P. A., Zou, H., & Waterhouse, A. L. (2001). Journal of Agricultural and Food Chemistry, 49, 1957-1965;2 - Roginsky, V., De Beer, D., Harbertson, J. F., Kilmartin, P. A., Barsukova, T., & Adams, D.O. (2006). Journal of the Science of Food and Agriculture, 86, 834-840;3 - Rodrigues, A., Silva Ferreira, A. C., Guedes de Pinho, P., Bento, F., & Geraldo, D. (2007). Journal of Agricultural and Food Chemistry, 55, 10557-10562;4 - Martins, R. C., Oliveira, R., Bento, F., Geraldo, D., Lopes, V. V., Guedes de Pinho, P., Oliveira, C. M., & Silva Ferreira, A. C. (2008). Journal of Agricultural and Food Chemistry, 56, 12092-12098;5 - Makhotkina, O., & Kilmartin, P. A. (2009). Journal of Electroanalytical Chemistry, 633, 165-174;6 - Silva Ferreira A. C., Caracterisation du Vieillissement du Vin de Porto (1998). These de Doctorat de L’Université Victor Segalen Bordeaux II. 1998, 593;7 - Oliveira, C. M., Silva Ferreira, A. C., Pinho, P. G., & Silva, A. M. S. (2008). Journal of Agricultural and Food Chemistry, 56, 10326-10331.IntroductionMaterial and MethodsLiquid-liquid extraction of wines. Extractions were performed according to themethodology published by (6). Antiradical activity. The antiradical activity ofwines were determined using the free radical method ABTS (7). Cyclicvoltammetry. Experiments were performed using a potentiostat (microAutolabType III with an Autolab Faraday Cage) and voltammograms were obtained witha scan rate of 100 mV with an increment potential of 2.4 mV, between 0 V to1.2 V. The working electrode was a 3 mm Glassy Carbon disk in combinationwith a Metrohm tipholder. A saturated calomel electrode was used as areference electrode in conjunction with a platinum counter electrode. GC/Massspectrometry. Samples were analysed using a Varian CP-450 gaschromatograph equipped with a Varian Saturn 240 MS. The mass range was 33m/z to 350 m/z, in Full Scan mode, and the column was a FactorFour capillaryVF-WAXms 15mX0.15mm ID with DF 0.15 µm from Varian. Raw voltammetricand chromatographic signals were processed using a methodology performedbased on R statistical programming (R-Project R, http://www.r-project.org/) andthen explored by multivariate analysis, namely, Principle Component Analysis(PCA).Cyclic VoltammetryTreatment IVoxygen additionFirst sampling point P1Last sampling point P6Concerning the GC-MS non-target approach PCA illustrate the global chemical differences of the wines. 0.0 0.2 0.4 0.6 0.8 1.0 1.20.0000.0020.0040.006(a)Potential (V)Current (A)-0.002 0.000 0.002 0.004 0.006 0.008-0.006-0.004-0.0020.000(b)Variance OneVariance Two0.90.951_40_F11 50_F11_50_F42_40_F12_40_F42_50_F12_50_F43_20_F43_30_F13_30_F43_40_F43_50_F13_50_F44_20_F44_30_F14_30_F44_40_F14_40_F44_50_F14_50_F45_20_F45_30_F15_30_F45_40_F15_50_F15_50_F46_20_F16_20_F46_30_F16_30_F46_40_F16_40_F46_50_F16_50_F4A supervised multivariate control chart was developed using control wine samples as reference . In this way, when white wines are plotted onto the chart, it was possible to monitor the oxidation status and to diagnose the effect of oxygen and temperature regimes.2-Furfural in the forced aged wines.Concentration in µg/L; F1 and F4 (oxygen saturation levels); 20, 30, 40, and 50ºC (temperature regimes).OCHO0500100015000 20 40 60[Conc]Time (days)F1F1_20F1_30F1_40F1_50 0500100015000 20 40 60[Conc]Time (days)F4F4_20F4_30F4_40F4_50Compounds not modulated by oxygen treatmentsMethional in the forced aged wines.Concentration in µg/L; F1 and F4 (oxygen saturation levels); 20, 30, 40, and 50ºC (temperature regimes).0.001.002.003.004.000 20 40 60[Conc]Time (days)F1F1_20F1_30F1_40F1_50 0.002.004.006.008.000 20 40 60[Conc]Time (days)F4F4_20F4_30F4_40F4_50Compounds modulated by oxygen treatmentsS HCH3Oa) Oxidation process and b) Chart controlPC1&PC2GC-MSConcerning cyclic voltammetry, signal processing techniques were used to decompose the multivariate data sets.Results have showed that oxygen consumption and temperature exposure decreases the antioxidant activity of theforced aged wine samples screening by voltammetric measurements. Furthermore, a supervised multivariatecontrol chart was developed using control wine samples as reference. In this way, when white wines are plottedonto the chart, it was possible to monitor the oxidation status and to diagnose the effect of oxygen and temperatureregimes. Additionally, results clearly demonstrate a “convolution” of chemical mechanisms. Same compounds werenot modulated by oxygen treatments, like 2-furfural and 5-metil-2-furfural, unlike methional andphenylacetaldehyde that were clearly related to the presence of oxygen. Furthermore, the annotation of interestingcompounds can be made and the identification and annotation of the major contributory compounds for samplesmetabolic variability can be achieve.ConclusionsResults have showed that oxygen consumption and temperature exposure decreasesthe antiradical activity of the forced aged wine samples, evaluated by the ABTSmethodology till 48%, for the IV treatment.Antiradical activityTreatment I: no oxygen addition (F1)V = 1000 mlT = 20 ºCV = 1000 mlT = 30 ºCV = 1000 mlT = 40 ºCV = 1000 mlT = 50 ºCTreatment II: 2 times saturated(F2)V = 1000 mlT = 20 ºCV = 1000 mlT = 30 ºCV = 1000 mlT = 40 ºCV = 1000 mlT = 50 ºCV = 1000 mlT = 20 ºCV = 1000 mlT = 30 ºCV = 1000 mlT = 40 ºCV = 1000 mlT = 50 ºCV = 1000 mlT = 20 ºCV = 1000 mlT = 30 ºCV = 1000 mlT = 40 ºCV = 1000 mlT = 50 ºCTreatment III: 3 timessaturated(F3)Treatment IV: saturated every sampling point  (F4)Forced Aging Protocol – 42 days (6 weeks)Fourteen litters of white wine (pH = 3.2): 4 oxygen regimes 

Wine oxidation profile accessed by voltammetric, antioxidant scavenging and GC-MS techniques

https://repositorio.ucp.pt/bitstream/10400.14/7724/3/com_inter_2011_ESB_100_Silva%20Ferreira_Ant%c3%b3nio%20C%c3%a9sar_08.pdf

Wine oxidation profile accessed by voltammetric, antioxidant scavenging and GC-MS techniques

Abstract

Similar works

Full text

Available Versions

Repositório Institucional da Universidade Católica Portuguesa