Evidence of Enzymatic and Chemical Interconversions of Barley Malt 3-Sulfanylhexanol Conjugates during Mashing.

Recent studies have highlighted in malt the occurrence of the glutathionylated precursor of 3-sulfanylhexanol (G-3SHol) at concentrations reaching hundreds of μg/kg. Here, SIDA-LC-MS/MS was used to investigate the potential conversion of G-3SHol to its dipeptide and cysteinyl analogues during mashing. At 45 and 55 °C, malt γGT and carboxypeptidase activities quickly degrade G-3SHol (up to 90% loss), first to the cysteinylglycine conjugate and then to the cysteine conjugate (up to 205% increase).

Malt and Hop as Sources of Thiol -Conjugates: Thiol-Releasing Property of Lager Yeast during Fermentation.

The contribution of polyfunctional thiols (PFTs) to the overall flavor of a lager beer has been well documented, but their origin remains unclear. In comparison with strains previously investigated (same conditions: 7 days at 24 °C, 3 days at 4 °C), we examined how yeasts are able to produce these PFTs from cysteinylated (Cys-) and glutathionylated (G-) conjugates. Up to 0.

Modulation of the Sulfanylalkyl Acetate/Alcohol Ratio and Free Thiol Release from Cysteinylated and/or Glutathionylated Sulfanylalkyl Alcohols in Beer under Different Fermentation Conditions.

The occurrence of a substantial pool of cysteinylated and glutathionylated forms of polyfunctional thiols has been evidenced for several dual-purpose hop varieties, and so is the ability of yeast to release free thiols from these forms through fermentation. The present work aimed to investigate the effect of temperature, wort density, maturation time, and strain on the efficiency of free thiol release by yeasts. Model media at 12, 15, or 17°P were spiked with three cysteinylated (Cys-) or three glutathionylated (G-) sulfanylalkyl alcohols (Cys- or G-3-sulfanylpentan-1-ol, 3-sulfanyl-4-methylpentan-1-ol, and 3-sulfanylhexan-1-ol), fermented for 7 days at 18, 24, and 28 °C, and kept at 4 °C for varying number of days.

Occurrence of Ehrlich-Derived and Varietal Polyfunctional Thiols in Belgian White Wines Made from Chardonnay and Solaris Grapes.

Although almost disappeared at the end of the 20th century, Belgian wine production reached a million liters in 2017. The aim of the present work was to identify aroma markers for two white cultivars widespread in Belgium: Chardonnay (the most commercially grown cultivar worldwide) and Solaris (an interspecific fungus-resistant variety). Specific -hydroxymercuribenzoic acid extraction followed by gas chromatography with a pulsed flame photometric detector was applied to single-varietal wine samples from 2015 to 2018 harvests.

First Evidence of the Cysteine and Glutathione Conjugates of 3-Sulfanylpentan-1-ol in Hop ( Humulus lupulus L.).

After evidence of the cysteinylated precursors of 3-sulfanyl-4-methylpentan-1-ol (Cys-26) and 3-sulfanylhexan-1-ol (Cys-23) in hop, S-glutathione precursors (G-23 and G-26) were recently discovered in different dual-purpose hop varieties. Because free 3-sulfanylpentan-1-ol (21) has also been detected in hop, the present work aimed to identify its potential precursors. The compounds S-3-(1-hydroxylpentyl)cysteine (Cys-21) and S-3-(1-hydroxylpentyl)glutathione (G-21) were first synthesized and characterized by nuclear magnetic resonance and high-resolution mass spectrometry.