LC-MS metabolomics shows a smart way to reduce sulfites in wine

O H _NH NH O NH₂ O SH O O O H O H _NH NH O NH₂ O S O O O H S O OH O

SO

₂

+ H

2

O

HSO

₃ -O H _NH NH O NH₂ O S O O O H O H NH NH O NH₂ O S O O O H

O

₂ O NH NH O OH O H S S O O OH O NH NH O OH O H SH O NH₂ S OH S O O O H O NH₂ S H OH

LC-MS METABOLOMICS SHOWS A SMART WAY TO REDUCE SULFITES IN WINE

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rs Panagiotis Arapitsas1*, Maurizio Ugliano2

Daniele Perenzoni1 , Andrea Angeli1 Paolo Pangrazzi3 , Fulvio Mattivi1

1_{Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach, via E. Mach 1, San Michele all’Adige, Italy}

2_{Nomacorc France, Domaine de Donadille, Avanue Yves Cazeaux, 30230 Rodilhan, France}

3_{MezzaCorona winery, 38016 Mezzocorona, Italy}

*panagiotis.arapitsas@fmach.it 0 1 2 3 4 5 6 7 8 9 IN Z M LR C H R T R M G R L-1 G R L-2 G R L-3 P N T -1 P N T -2 P N T -3 P N T -4 P N T -5 T P O ( p p m ) Bottling High O2 High O2 Bottling Low O2 Low O2

Experimental Design

The sample set included 12 white wines from 6 varieties. 10 samples of each wine were bottled using the standard industrial process, with inert headspace and variable exposure to oxygen (Low O₂), along with a further 10 bottles produced using the same line, but without inert gas and with extra headspace (High O₂). The wines were analyzed after two months of storage. Pinot gris Grillo Chardonnay Muller Thurgau Traminer Inzolia x 5 x 3 x 1 x 1 x 1 x 1 x 10 x 10 x 10 x 10 x 10 x 10 Variety Wine Bottles bottled Low O₂ High O₂

The mean concentrations of total package oxygen (TPO) in each wine under the two bottling conditions (respectively, High vs Low O₂) at the time of bottling and after two months of storage.

The impact of minute amounts of headspace oxygen on the post-bottling development of wine is generally considered to be very important, since oxygen, packaging and storage conditions can either damage or improve the quality of wine, in terms of its characteristics.

Introduction

PNT GRL CHR MLR TRM INZ Code x 10 x 10 x 10 x 10 x 10 x 10 Total 240 bottles

Results I

NomaSense™ oxygen analyzer

For further information read: Arapitsas, P.; Ugliano, M.; Perenzoni, D.; Angeli, A.; Pangrazzi, P.; Mattivi, F. Wine metabolomics reveals new sulfonated products in bottled whitewines, promoted by small amounts of

oxygen, Journal of Chromatography A, vol. 1429, pp. 155-165, 2016.

UHPLC-QTof MS untargeted analysis pointed out the power of metabolomics to discriminate the various wines; but supervised multivariate statistical analysis were necessary to detect O₂ related markers. This was due to the “statistical noise” generated by the cultivar variability.

Results II

Low O₂ High O₂

New reactions discovered: The main reactions driven by O₂ were involving Sulfur. The antioxidant SO₂, added to protect wine from unwanted reactions, takes part in various reactions, several of which were unknown in wine to date and would appear to be of practical significance.

Possible additive interaction effects, between SO₂ and glutathione, should be revaluated, since these could also turn out to be antagonistic, and their co-addition/co-presence could provide less effective protection.

Wines containing large amounts of indoles might require the addition of larger amounts of SO₂ or/and should be bottled under low oxygen conditions.

Results III

N H O O OH O OH OH O H OH N H O O OH O OH OH O H OH S O OH O N H OH S O O OH N H OH O₂, HSO-₃ O₂, HSO-₃ O₂, HSO-₃ O₂, HSO-₃ pantetheine cysteine

The co-presence of glutathione (GSH) and SO₂ in wine has as a result the formation of S-sulfonated glutathione (GSSO₃H). The mechanism of the reaction requires first the oxidation of GSH to GSSG (glutathione disulfide), which reacts very fast to produce GSSO₃H. This is the cause why GSSG is not detectable in wine.

indole-3-lactic acid hexoside

tryptophol

GSH

GSSG