Macrowine 2021
IVES 9 IVES Conference Series 9 Relevance of the polyphenolic profile during oxidative aging in the accumulation and disappearance of oxidative and varietal aromas

Relevance of the polyphenolic profile during oxidative aging in the accumulation and disappearance of oxidative and varietal aromas

Abstract

The main objective of this work is to study and model the impact of the polyphenolic profile on the stability and quality of wine aroma during oxidative aging. Aromas considered in the study are grape-derived varietal aromas, such as linalool, geraniol and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN), yeast-released varietal mercaptans, such as 4-mercapto-4-methyl-2-pentanone (4MMP), 3-mercaptohexyl acetate (MHA) and 3-mercaptohexan-1-ol (3MH)) and also oxidation-related aroma compounds, such as acetaldehyde and Strecker aldehydes: isobutyraldehyde, 2-methylbutyraldehyde, isovaleraldehyde, methional and phenylacetaldehyde. Fifteen aromatic phenolic fractions (FFAs) were extracted from garnacha, moristel and tempranillo grapes; FFAs were chemically characterized and were further reconstituted with water, alcohol, metal cations, amino acids and polyfunctional mercaptans so that differences were limited to the polyphenolic profile and to levels of precursors to varietal aroma compounds. Reconstituted samples were supplied with oxygen (50 mg/L) and aged during 35 days at 35ºC. Results show that the accumulation of acetaldehyde is uniform and very low in all the FFAs, confirming previous results about the low accumulation of this compound during oxidation. Nevertheless, acetaldehyde accumulation seems to be correlated with the sum of phenolic acids. Accumulation of Strecker aldehydes between samples differs by a 2.5 factor, with much higher levels in reconstitutions with FFAs from Garnacha and Moristel varieties. Levels of Strecker aldehydes were positively correlated to the sum of flavanols, phenolic acids and with the percentage of unpigmented tannins. Also, they appear to be negatively correlated with color, pigmented and total tannin concentrations and delphinidins. Polyfunctional mercaptans reacted spontaneously even in anoxia, so that final levels were significant only in unoxidized controls. In these samples, levels between different FFAs differed by factors of up to 2.6 and were negatively correlated to the contents of unpigmented tannins. The other varietal aromas (linalool, geraniol and TDN), were not affected by oxidation. All of this demonstrates that the phenolic composition plays a crucial role in the development of Strecker aldehydes during oxidative aging, likely due the differential reactivity of the quinones formed. The strong reactivity of wine polyphenols to polyfunctional mercaptans was not expected and should be further studied.

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Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Elena Bueno-Aventín

Laboratory for Aroma Analysis and Enology (LAAE), Department of Analytical Chemistry, Faculty of Chemistry. E-50009, Zaragoza, Spain,Vicente Ferreira-González, Ana Escudero-Carra   Laboratory for Aroma Analysis and Enology (LAAE), Department of Analytical Chemistry, Faculty of Chemistry. E-50009, Zaragoza, Spain

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Keywords

polyphenol; acetaldehyde; aldehydes; polyfunctional mercaptans; oxidation

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Protected Designation of Origin (D.P.O.) Valdepeñas: classification and map of soils

The objective of the work described here is the elaboration of a map of the different types of vineyard soils that to guide the famers in the choice of the most productive vine rootstocks and varieties. 90 vineyard soils profiles were analysed in the entire territory of the Origen Denominations of Valdepeñas. The sampling was carried out in 2018 (June to October) by making a sampling grid, followed by photointerpretation and control in the field. The studied soils can be grouped into 9 different soil types (according to FAO 2006 classification): Leptosols, Regosols, Fluvisols, Gleysols, Cambisols, Calcisols, Luvisols and Anthrosols. A map showing the soil distribution with different type of soils has been made with the ArcGIS program. Regarding to the choice of rootstock, Calcisoles are soils with a high active limestone content, so the rootstocks used in these soils must be resistant to this parameter; Luvisols are deep soils with high clay content, so they will support vigorous rootstocks. Because the cartographic units are composed of two or more subgroups, with are associated in variable proportions, 9 different soil associations have been established; Unit 1: Leptosols, Cambisols and Luvisols (80%, 15% and 5% respectively); Unit 2: Cambisols with Regosols and Luvisols (40%, 30% and 30% respectively); Unit 3: Cambisols and Gleysols with Regosols (40%, 40% and 20% respectively); Unit 4: Regosols with Cambisols, Leptosols and Calcisols (40%, 30%, 15% and 15% respectively); Unit 5: Cambisols, Leptosols, Calcisols and Regosols (25% each of them); Unit 6: Luvisols with Cambisol and Calcisols (80%, 10% and 10% respectively); Unit 7: Luvisols and Calcisols with Cambisols (40%, 40% and 20% respectively); Unit 8: Calcisols with, Cambisols and Luvisols (80%, 10% and 10% respectively); Unit 9: Anthrosols. These study allow to elaborate the first map of vineyard soils of this Protected Designation of Origin in Castilla-La Mancha.

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Macrowine 2021
IVES 9 IVES Conference Series 9 Relevance of the polyphenolic profile during oxidative aging in the accumulation and disappearance of oxidative and varietal aromas

Relevance of the polyphenolic profile during oxidative aging in the accumulation and disappearance of oxidative and varietal aromas

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