A new analytical method to measure S‐methyl‐l‐methionine in grape juice reveals the influence of yeast on dimethyl sulfide production during fermentation

Abstract

BACKGROUND Dimethyl sulfide (DMS) is a small sulfur‐containing impact odorant, imparting distinctive positive and / or negative characters to food and beverages. In white wine, the presence of DMS at perception threshold is considered to be a fault, contributing strong odors reminiscent of asparagus, cooked cabbage, and creamed corn. The source of DMS in wine has long been associated with S‐methyl‐l‐methionine (SMM), a derivative of the amino acid methionine, which is thought to break down into DMS through chemical degradation, particularly during wine ageing. RESULTS We developed and validated a new liquid chromatography–tandem mass spectrometry (LC–MS/MS) method with a stable isotope dilution assay (SIDA) to measure SMM in grape juice and wine. The application of this new method for quantitating SMM, followed by the quantitation of DMS using headspace‐solid phase micro‐extraction coupled with gas chromatography–mass spectrometry (HS‐SPME/GC–MS), confirmed that DMS can be produced in wine via the chemical breakdown of SMM to DMS, with greater degradation observed at 28 °C than at 14 °C. Further investigation into the role of grape juice and yeast strain on DMS formation revealed that the DMS produced from three different Sauvignon blanc grape juices, either from the SMM naturally present or SMM spiked at 50 mmol L−1, was modulated depending on each of the four strains of Saccharomyces cerevisiae wine yeast used for fermentation. CONCLUSION This study confirms the existence of a chemical pathway to the formation of DMS and reveals a yeast‐mediated mechanism towards the formation of DMS from SMM during alcoholic fermentation. © 2019 Society of Chemical Industry

Aroma‐volatile profile and its changes in Australian grown black Périgord truffle (Tuber melanosporum) during storage

“…No significant change of DMS throughout the storage period was apparent but DMSO gradually decreased (P < 0.05) (Table 1). The decrease of dimethyl sulfoxide could be due to the reductase activity of the microbial population transforming dimethyl sulfoxide into dimethyl sulphide, which was previously found in the fermentation process of various wines and beers (Silva Ferreira et al, 2003, Deed et al, 2019, Bamforth, 2014Szlavko & Anderson, 1979).…”

Inter‐regional survey of the New Zealand Pinot noir fermentative sulfur compounds profile

“…This molecule is known to accumulate during ageing via the degradation of its main precursor (i.e. S ‐methylmethionine), 33 whereas a recent study has shown that, even though marginal, yeast and fermentation conditions can also play an effect in the production of dimethyl sulfide in wine 34 . Here, average levels of DMS were quantified at 37.6 ± 19.1 μg L −1 , which displays both the high presence of this molecule, as well as its fluctuation between samples.…”

Sensory characterisation of wines without added sulfites via specific and adapted sensory profile

“…Other studies have shown that dimethyl sulfide has an impact on blackcurrant aromas through perceptual interactions in low concentrations (Escudero et al, 2007;Lytra et al, 2014). However, the dimethyl sulfide formed during alcoholic fermentation (therefore by yeasts (Deed et al, 2019)) is mainly eliminated because this molecule is very volatile. Its concentration after 1.5 years is around 10µg/L (Segurel et al, 2004) and has an impact on blackcurrant aromas.…”