Polysulfides accumulation in white wines produced from different oenological yeasts

Untargeted polysulfide omics analysis of alternations in polysulfide production during the germination of broccoli sprouts

Higher consumption of broccoli (Brassica oleracea var. italica) is associated with a reduced risk of cardiometabolic diseases, neurological disorders, diabetes, and cancer. Broccoli is rich in various phytochemicals, including glucosinolates, and isothiocyanates. Moreover, it has recently reported the endogenous production of polysulfides, such as cysteine hydropersulfide (CysS2H) and glutathione hydropersulfide (GS2H), in mammals including humans, and that these bioactive substances function as potent antioxidants and important regulators of redox signaling in vivo. However, few studies have focused on the endogenous polysulfide content of broccoli and the impact of germination on the polysulfide content and composition in broccoli. In this study, we investigated the alternations in polysulfide biosynthesis in broccoli during germination by performing untargeted polysulfide omics analysis and quantitative targeted polysulfide metabolomics through liquid chromatography-electrospray ionization-tandem mass spectrometry. We also performed 2,2-diphenyl-1-picrylhydrazyl radical-scavenging assay to determine the antioxidant properties of the polysulfides. The results revealed that the total polysulfide content of broccoli sprouts significantly increased during germination and growth; CysS2H and cysteine hydrotrisulfide were the predominant organic polysulfide metabolites. Furthermore, we determined that novel sulforaphane (SFN) derivatives conjugated with CysS2H and GS2H were endogenously produced in the broccoli sprouts, and the novel SFN conjugated with CysS2H exhibited a greater radical scavenging capacity than SFN and cysteine. These results suggest that the abundance of polysulfides in broccoli sprouts contribute to their health-promoting properties. Our findings have important biological implications for the development of novel pharmacological targets for the health-promoting effects of broccoli sprouts in humans.

A method for the quantitative and reversible trapping of sulfidic gases from headspaces and its application to the study of wine reductive off-odors

Some relevant food systems release tiny amounts of sulfidic gases, whose measurement is difficult because of their inherent instability. The present paper demonstrates that Cu(I) solutions trap quantitatively and stabilize sulfidic gases. Once trapped, the gases remain stable for weeks at 4 °C and at least 8 days at 75 °C. Trapped gases can be quantitatively released with tris(2-carboxyethyl) phosphine (TCEP) and brine dilution and then determined by GC. Trapping solutions, placed in 20-mL opened vials housed in 100 mL hermetically-sealed flasks containing wine in anoxia, have been used to monitor the release of sulfidic gases by wines, revealing that at 50 °C, up to 400 μg/L of H₂S and 58 μg/L of MeSH can be released in 68 days, and 3-5 times more at 75 °C in 28 days. The possibility to differentiate between released and accumulated amounts provides key clues to understanding the fate of sulfidic gases in wine and other food systems.

Monitoring hydrogen sulfide de-novo formation from polysulfides present in wine using ion chromatography and ultra high-pressure liquid chromatography combined with fraction collection and high-resolution mass spectrometry

The study of polysulfides has been a recent topic of interest for wine research due to the possibility of these compounds to release hydrogen sulfide (H₂S) during storage. However, studying these compounds has been challenging for several reasons. Polysulfides are low in concentration in natural samples, they are chemically unstable and pure standards of the single compounds (RS_nR with n > 2) are not commercially available. In the present study, a method was developed in order to collect a single polysulfide and study its degradation and the consequent formation of H₂S. For this approach, ultra-high pressure liquid chromatography was used with an integrated fraction collector and subsequently coupled to high resolution mass spectrometry. After fractionation, the degradation of the di-cysteinyl pentasulfide (CS₅C) was induced by exposure to 30 °C and the H₂S formation was measured in parallel using ion-exchange chromatography. This method showed the evolutions of different polysulfides and the H₂S release originating from the target compound, an observation that to the best of our knowledge has never been made before. The method in the present study demonstrated promising applications for polysulfide studies and brought us a step closer to the understanding of the chemistry of polysulfides in wine.