One thing that will definitely ruin a wine is an unpleasant aroma. Such malodorous wines could soon be saved, however, with a little bit of help from gold nanoparticles.
Wines get their aroma from the presence of what are known as volatile sulfur compounds (VSCs). Some of these produce a desired scent, but others smell more like rotten eggs, rubber and other things you wouldn't want to drink. And while copper sulfate is often added to wines to neutralize these problematic VSCs, it may negatively affect the wines' flavor.
Seeking a more effective alternative, scientists at Australia's Flinders University devised a process which begins with a thin plasma polymer coating being applied to the surface of a neutral substrate. Gold nanoparticles are then immobilized on that coating – gold is used because it's known to bind with certain sulfur molecules.
In lab tests, microscope slides that had received the surface treatment were placed in 40-milliliter samples of white and red wines that had naturally high levels of undesirable VSCs.
When the slides were removed 24 hours later, their nanoparticles were found to have neutralized up to 45% of the free hydrogen sulfide in the wines, along with other unwanted VSCs like methanethiol. And importantly, the particles outperformed copper sulfate which was used on matching samples.
Although more research needs to be conducted, it is hoped that one day the treatment could be applied to surfaces utilized in the winemaking industry such as those of filtration devices, decanters and packaging materials.
A paper on the study, which was led by Dr. Agnieszka Mierczynska-Vasilev and Prof. Krasimir Vasilev, was recently published in the journal npj Science of Food.
Source: Flinders University