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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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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VineyardFACE: Investigation of a moderate (+20%) increase of ambient CO2 level on berry ripening dynamics and fruit composition

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The present study aims to investigate the effect on fruit composition under a moderate increase (+20%; eCO2) of carbon dioxide concentration, as predicted for 2050 on both Riesling and Cabernet Sauvignon. Berry composition was determined for primary (sugars, organic acids, amino acids) and secondary metabolites (anthocyanins). Special focus was given on monitoring of berry diameter and ripening rates throughout three growing seasons. Compared to previous results of the early adaptative phase of the vines [1], our results show little effect of eCO2 treatment on primary metabolites composition in berries. However, total anthocyanins concentration in berry skin was lower for eCO2 treatment in 2020, although the ratio between anthocyanins derivatives did not differ.
[1] Wohlfahrt Y., Tittmann S., Schmidt D., Rauhut D., Honermeier B., Stoll M. (2020) The effect of elevated CO2 on berry development and bunch structure of Vitis vinifera L. cvs. Riesling and Cabernet Sauvignon. Applied Science Basel 10: 2486

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