Background and aims: Varietal thiols characterize the typical aroma of several white wines, as Sauvignon blanc. Their presence was suggested in two Sicilian grape cultivars, Catarratto Bianco Comune (CBC) and Grillo, thought it was not analytically proved to date. Methods and Results: Varietal thiol precursors and free varietal thiols were assessed in CBC and Grillo grapes, musts and wines by UPLC/high resolution mass spectrometry (HRMS). The isobaric compounds S-3-(hexanal)-glutathione (GSH-3MHAl) and S-3-(4-mercapto-4-methylpentan-2-one)-glutathione (GSH-4MMP) were discriminated by comparing their accurate masses and HR-MS/MS spectra with those of their synthetic standards. GSH-3MHAl, S-3-(hexan-1-ol)-glutathione (GSH-3MH) and S-3-(hexan-1-ol)-cysteine occurred in grape, must and wine, while GSH-4MMP and its hydrolysed forms did not. Their amounts decreased during the industrial winemaking processes, mostly following the grape pressing. We compared clarification conditions exposing must to either air or CO2 in terms of thiol precursors’ and free thiols’ content in wine. However, negligible differences were observed. Concentrations of free thiols in the range 400–1100 ng/L were found in the wines and they were not affected to the two clarification conditions adopted. Conclusion: The isobaric GSH-3MHAl and GSH-4MMP were clearly distinguished for the first time by UPLC-HRMS through their retention times and MS spectra. The varietal thiols were firstly revealed CBC and Grillo wines. The air-free and air- exposed clarification poorly affected the levels of varietal thiols. Significance of the study: This research highlights the major impact of the varietal thiols (mainly 3–mercapto-hexan-1-ol and its acetate form) on the sensory properties of CBC and Grillo wines.
Thiol precursors in Catarratto Bianco Comune and Grillo grapes and effect of clarification conditions on the release of varietal thiols in wine / D. Fracassetti, M. Stuknyte, C. La Rosa, M. Gabrielli, I. De Noni, A. Tirelli. - In: AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH. - ISSN 1322-7130. - 24:1(2018), pp. 125-133. [10.1111/ajgw.12311]
Thiol precursors in Catarratto Bianco Comune and Grillo grapes and effect of clarification conditions on the release of varietal thiols in wine
D. FracassettiPrimo
;M. StuknyteSecondo
;C. La Rosa;M. Gabrielli;I. De NoniPenultimo
;A. Tirelli
Ultimo
2018
Abstract
Background and aims: Varietal thiols characterize the typical aroma of several white wines, as Sauvignon blanc. Their presence was suggested in two Sicilian grape cultivars, Catarratto Bianco Comune (CBC) and Grillo, thought it was not analytically proved to date. Methods and Results: Varietal thiol precursors and free varietal thiols were assessed in CBC and Grillo grapes, musts and wines by UPLC/high resolution mass spectrometry (HRMS). The isobaric compounds S-3-(hexanal)-glutathione (GSH-3MHAl) and S-3-(4-mercapto-4-methylpentan-2-one)-glutathione (GSH-4MMP) were discriminated by comparing their accurate masses and HR-MS/MS spectra with those of their synthetic standards. GSH-3MHAl, S-3-(hexan-1-ol)-glutathione (GSH-3MH) and S-3-(hexan-1-ol)-cysteine occurred in grape, must and wine, while GSH-4MMP and its hydrolysed forms did not. Their amounts decreased during the industrial winemaking processes, mostly following the grape pressing. We compared clarification conditions exposing must to either air or CO2 in terms of thiol precursors’ and free thiols’ content in wine. However, negligible differences were observed. Concentrations of free thiols in the range 400–1100 ng/L were found in the wines and they were not affected to the two clarification conditions adopted. Conclusion: The isobaric GSH-3MHAl and GSH-4MMP were clearly distinguished for the first time by UPLC-HRMS through their retention times and MS spectra. The varietal thiols were firstly revealed CBC and Grillo wines. The air-free and air- exposed clarification poorly affected the levels of varietal thiols. Significance of the study: This research highlights the major impact of the varietal thiols (mainly 3–mercapto-hexan-1-ol and its acetate form) on the sensory properties of CBC and Grillo wines.File | Dimensione | Formato | |
---|---|---|---|
Fracassetti_et_al-2018-Australian_Journal_of_Grape_and_Wine_Research.pdf
accesso aperto
Tipologia:
Publisher's version/PDF
Dimensione
1.05 MB
Formato
Adobe PDF
|
1.05 MB | Adobe PDF | Visualizza/Apri |
Manuscript_2018 06 24.pdf
accesso aperto
Descrizione: Articolo principale
Tipologia:
Post-print, accepted manuscript ecc. (versione accettata dall'editore)
Dimensione
661.77 kB
Formato
Adobe PDF
|
661.77 kB | Adobe PDF | Visualizza/Apri |
Figures.pdf
accesso riservato
Descrizione: Figure dei dati sperimentali
Tipologia:
Post-print, accepted manuscript ecc. (versione accettata dall'editore)
Dimensione
290.86 kB
Formato
Adobe PDF
|
290.86 kB | Adobe PDF | Visualizza/Apri Richiedi una copia |
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.