Magnetic nanoparticles used to clarify white wine – with less waste

Would you buy a cloudy white wine? Probably not, which is why vintners go to great lengths to clarify their product. Soon, they could do so more efficiently than ever, using newly created nanoparticles.

Ordinarily, white wines are commercially clarified via the use of powdered bentonite clay. Once added to the wine, the clay particles bond with suspended protein particles, causing both to settle to the bottom of the wine-making vessel. The now-clarified wine is subsequently poured off the top, leaving the sediment behind.

Unfortunately, though, the clay particles also absorb some of the wine in the process. According to scientists from the University of South Australia, this results in a loss of wine volume of about 3 percent, which translates into annual financial losses of approximately $100 million in Australia alone.

Led by Dr. Agnieszka Mierczynska-Vasilev, the researchers set out to develop a less wasteful alternative. They ultimately created magnetic nanoparticles that are coated with acrylic acid polymers, the latter of which bond with the unwanted protein particles in white wine. Instead of settling to the bottom, though, the protein-loaded nanoparticles are then removed simply by placing a magnet in the wine.

And what's more, they can be "regenerated" (cleaned up) and reused multiple times. In lab tests performed on unclarified 2017 Sauvignon Blanc, Semillon and Chardonnay, the nanoparticles were found to remove 98 percent of haze-forming proteins per treatment, and they did so consistently over the course of 10 consecutive treatments. There was reportedly no effect on the wines' color, aroma or other factors.

"While there is still some way to go before the technology can be practically applied in wineries, and the need to obtain regulatory approval both in Australia and overseas, given the clear economic, sustainable and sensory benefits, this nanotechnology has a very strong potential for adoption," says Mierczynska-Vasilev.

A paper on the research was recently published in the journal Foods.

And this isn't the first time we've heard about magnetic nanoparticles being used to treat wine. Previously, scientists at Australia's University of Adelaide utilized them to remove chemical compounds known as alkylmethoxypyrazines, which can actually affect a wine's flavor and aroma.

Source: University of South Australia