Investigation of Thiol Levels in Young Commercial South African Sauvignon Blanc and Chenin Blanc Wines Using Propiolate Derivatization and GC-MS/MS

  • C. Coetzee Institute for Grape and Wine Sciences, Stellenbosch University, Stellenbosch
  • A. Schulze Institute for Grape and Wine Sciences, Stellenbosch University, Stellenbosch
  • L. Mokwena Central Analytical Facility, Stellenbosch University, Stellenbosch
  • W.J. du Toit Department of Viticulture and Oenology, Stellenbosch University, Stellenbosch
  • A. Buica Department of Viticulture and Oenology, Stellenbosch University, Stellenbosch

Abstract

In this work, the ethyl propiolate method for analysing thiols in white wine by GC-MS, originally proposed by Herbst-Johnstone et al.) (2013), has been adapted to GC-MS/MS and has been validated. The method performance has shown improvement in terms of sensitivity (limit of detection, LOD) and of the number of compounds measured. In addition to 3-mercaptohexanol (3MH), 3-mercaptohexyl acetate (3MHA), and 4-mercapto-4-methylpentan-2-one (4MMP), the adapted method can also measure 2-furanmethanethiol (FMT) and makes use of a commercially-available internal standard (IS), 4-methoxy-2-methyl-2-butanethiol (4M2M2B, IS). The proposed method was applied to determine thiol levels in young commercial South African Sauvignon and Chenin Blanc wines. The samples (n=20 for each cultivar) were chosen according to a high frequency of the typical descriptors associated with this class of impact compounds. 3MH was found at 178-904 ng/L and 99-1124 ng/L, and 3MHA at 23-151 ng/L and 5-253 ng/L in Sauvignon and Chenin Blanc respectively. 4MMP was present in Sauvignon Blanc in concentrations up to 21.9 ng/L, but in none of the Chenin Blanc samples.

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Author Biography

A. Buica, Department of Viticulture and Oenology, Stellenbosch University, Stellenbosch

Researcher in Oenology

Depatrment of Viticulture and Oenology

References

Capone, D.L., Ristic, R., Pardon, K.H. & Jeffrey, D.W., 2015. Simple quantitative determination of potent thiols at ultratrace levels in wine by derivatization and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis. Analytical Chemistry 87(2), 1226–1231.

Coetzee, C. & du Toit, W.J., 2012. A comprehensive review on Sauvignon blanc aroma with a focus on certain positive volatile thiols. Food Research International 45(1), 287–298.

Danilewicz, J.C., Seccombe, J.T. & Whelan, J., 2008. Mechanism of interaction of polyphenols, oxygen, and sulfur dioxide in model wine and wine. American Journal of Enology and Viticulture 59(2), 128–136.

Herbst-Johnstone, Piano, F., Duhamel, N., Barker, D. & Fedrizzi, B., 2013. Ethyl propiolate derivatisation for the analysis of varietal thiols in wine. Journal of Chromatography A, 1312, pp.104–110.

Musumeci, L.E., Ryona, I., Pan, B.S., Loscos, N., Feng, H., Cleary, M.T. & Sacks, G.L., 2015. Quantification of polyfunctional thiols in wine by HS-SPME-GC-MS following extractive alkylation. Molecules 20(7), 12280–12299.

Piano, F., Fracassetti, D, Buica, A., Stander, M., du Toit, W.J., Borsa, D. & Tirelli, A., 2015. Development of a novel liquid/liquid extraction and ultra-performance liquid chromatography tandem mass spectrometry method for the assessment of thiols in South African Sauvignon Blanc wines. Australian Journal of Grape and Wine Research, 21(1), 40–48.

Tominaga, T., Blanchard, L., Darriet, P. & Dubourdieu, D., 2000. A Powerful Aromatic Volatile Thiol, 2-Furanmethanethiol, Exhibiting Roast Coffee Aroma in Wines Made from Several Vitis vinifera Grape Varieties. Journal of Agricultural and Food Chemistry 48(5), 1799–1802.

Tominaga, T., Murat, M.-L. & Dubourdieu, D., 1998. Development of a method for analyzing the volatile thiols involved in the characteristic aroma of wines made from Vitis vinifera L. cv. Sauvignon blanc. Journal of Agricultural and Food Chemistry 46(3), 1044–1048.

Vichi, S., Cortés-Francisco, N. & Caixach, J., 2015. Analysis of volatile thiols in alcoholic beverages by simultaneous derivatization/extraction and liquid chromatography-high resolution mass spectrometry. Food Chemistry 175, 401–408.

Wilson, C.L., 2017. Chemical evaluation and sensory relevance of thiols in South African Chenin Blanc wines. MSc Thesis, Stellenbosch University, Private Bag X1, 7602 Matieland (Stellenbosch), South Africa.

Van Wyngaard, E., 2013. Volatiles playing an important role in South African Sauvignon blanc wines. MSc Thesis, Stellenbosch University, Private Bag X1, 7602 Matieland (Stellenbosch), South Africa

Published
2018-10-05
Section
Articles