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Magnetic nanoparticles attached to polymers have been successfully used to target and remove unwanted flavour compounds from wine.

Researchers at the ���˴�Ƭ in South Australia have developed a polymer for soaking up methoxypyrazines in Cabernet Sauvignon, a compound known to produce an undesirable green capsicum aroma.

They attached magnetic nanoparticles to the polymers and used magnets to remove the polymers from the wine once the compound had been extracted.

���˴�Ƭ Associate Professor in Wine Science  said magnetic polymers could potentially be used to target and remove other wine faults, noting that previous solutions relied on the disagreeable compounds being masked or settled to the bottom of tanks after using “fining” agents.

“There are patents out there around using molecularly imprinted polymers for taint removal from wine and also for removing methoxypyrazines, but I think the novelty really is in having the attached magnetic nanoparticles and to my knowledge it is the first time that it’s been applied to wine like this,” Associate Professor Jeffery said.

“The idea would need to be very selective for the compounds you’re wanting to use and that’s been the problem with other treatments, they’re quite non-selective.”

The researchers tested the magnetic polymers in Cabernet Sauvignon spiked with a perceptible amount of an alkyl methoxypyrazine known to occur in the variety in cool climate regions or if fruit is picked too early.

Using gas chromatography and mass spectrometry, the research team concluded that the magnetic polymers removed the compound from Cabernet Sauvignon more effectively than alternative methods. A group of taste testers also found the new approach removed these molecules without dampening the wine’s distinct aroma intensity.

The researchers also found the polymers could be regenerated and used five times without losing any ability to remove the targeted compound.

As the unwanted compound is in the fruit and not modified by the winemaking process, Associate Professor Jeffery said the magnetic polymers would likely be best used at the juice stage but could theoretically be used at any point during winemaking.

However, he said much more research, including a techno-economic analysis, would be required before the findings could be commercialised.

“There’s a lot of work that needs to be done still to figure out how you would best implement this in a winery,” Associate Professor Jeffery said.

“We just used bar magnets in the lab to remove the magnetic polymers but on an industrial scale you would need to use something a bit more sophisticated like an electro magnet.”

South Australia produces about 50 per cent of Australia’s wine and is home to the leading regions of �����Ի��� and brands including ,��,�������Ի���.

�ճ�������˴�Ƭ’s Waite Campus is part of Australia’s largest wine research hub in Adelaide’s southern suburbs, which also includes the ,�� and the university’s teaching winery.

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