Handheld methanol detector for beverage analysis: interlaboratory validation.

Methanol is a toxic alcohol contained in alcoholic beverages as a natural byproduct of fermentation or added intentionally to counterfeits to increase profit. To ensure consumer safety, many countries and the EU have established strict legislation limits for methanol content. Methanol concentration is mostly detected by laboratory instrumentation since mobile devices for routine on-site testing of beverages in distilleries, at border stations or even at home are not available.

Mixed yeast communities contribute to regionally distinct wine attributes.

There is evidence that vineyard yeast communities are regionally differentiated, but the extent to which this contributes to wine regional distinctiveness is not yet clear. This study represents the first experimental test of the hypothesis that mixed yeast communities-comprising multiple, region-specific, isolates, and species-contribute to regional wine attributes. Yeast isolates were sourced from uninoculated Pinot Noir fermentations from 17 vineyards across Martinborough, Marlborough, and Central Otago in New Zealand.

Characterization of polysulfides in Saccharomyces cerevisiae cells and finished wine from a cysteine-supplemented model grape medium.

Polysulfide degradation in wine can result in hydrogen sulfide (HS) release, imparting a rotten-egg smell that is detrimental to wine quality. Although the presence of wine polysulfides has been demonstrated, their biogenesis remains unclear. This study investigated the role of Saccharomyces cerevisiae in polysulfide formation during fermentation, with and without 5 mM cysteine supplementation as an HS source.

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

Background: New Zealand Pinot noir is gaining increasing attention both in New Zealand and internationally, becoming the second largest grape variety for both plantings and export. Despite the growing furore around this variety, the current coverage of the volatile chemical profile remains limited, with a lack of information on the fermentative sulfur compounds content in New Zealand Pinot noir wines.

Results: Thirty-five Pinot noir wines from three different vintages (i.

Iterative synthetic strategies and gene deletant experiments enable the first identification of polysulfides in Saccharomyces cerevisiae.

New evidence on the role of H2S as a gasotransmitter suggests that the true signalling effectors are polysulfides. Both oxidized polysulfides and hydropolysulfides were synthesized and their presence in S. cerevisiae was observed for the first time.

The impact of postharvest ultra-violet light irradiation on the thiol content of Sauvignon blanc grapes.

Sauvignon blanc grapes were exposed to an ultra-violet (UV) light source post-hand harvest (whole bunches) or post-machine harvest. The thiol precursors S-3-(hexan-1-ol)-l-cysteine (Cys-3MH) and S-3-(hexan-1-ol)-l-glutathione (GSH-3MH) were quantified in the juices before and after UV treatment. Results showed that irradiation of the grapes with UV light had little to no effect on the thiol precursors.