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. Stuknytė, C. La Rosa, Mario Gabrielli, I. De Noni, A. Tirelli*

*Autore corrispondente per questo lavoro

Risultato della ricerca: Contributo in rivistaArticolo

6 Citazioni (Scopus)

Abstract

Background and Aims: Varietal thiols characterise the typical aroma of several white wines, such as Sauvignon Blanc. Their presence and sensory perception were suggested in two Sicilian grape cultivars, Catarratto Bianco Comune (CBC) and\r\nGrillo, though it has not been analytically proven.\r\nMethods and Results: Varietal thiol precursors and free varietal thiols were assessed in CBC and Grillo grapes, musts and wines by ultra-performance liquid chromatography/electrospray ionisation high-resolution MS. The isobaric compounds including S-3-(hexanal)-glutathione and S-3-(4-mercapto-4-methylpentan-2-one)-glutathione (GSH-4MMP) were distin- guished by comparing their accurate masses and high-resolution-MS/MS spectra with those of their synthetic standards. S-3-(Hexanal)-glutathione, S-3-(hexan-1-ol)-glutathione and S-3-(hexan-1-ol)-cysteine were found in grape, must and wine, whereas GSH-4MMP and its hydrolysed forms were not found. Their concentration decreased during winemaking, mostly after grape pressing. We compared the effect of clarification conditions based on the exposure of must to either air or CO2 on the concentration of thiol precursors and free thiols in wine; however, negligible differences were observed. The concentration of free thiols in the wines was found to be in the range 400–1100 ng/L and they were unaffected by the two clarification conditions tested.\r\nConclusions: The isobaric S-3-(hexanal)-glutathione and GSH-4MMP were clearly distinguished for the first time by ultra- performance liquid chromatography/high-resolution MS through their retention times and MS spectra. These varietal thiols were revealed in CBC and Grillo wines for the first time. The air-free and air-exposed clarification treatments had little effect on the concentration of the varietal thiols.\r\nSignificance of the Study: This study 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.
Lingua originaleInglese
pagine (da-a)125-133
Numero di pagine9
RivistaAustralian Journal of Grape and Wine Research
Volume24
Numero di pubblicazione1
DOI
Stato di pubblicazionePubblicato - 2018

All Science Journal Classification (ASJC) codes

  • Orticoltura

Keywords

  • Catarratto Bianco Comune cultivar
  • Grillo cultivar
  • UPLC/ESI-HRMS
  • thiol precursors
  • varietal thiols

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