Bentonite fining to remove haze-forming proteins is a key step in the production of white and rosé wines, but has some drawbacks including wine losses and waste disposal issues. A new separation technology is showing potential as a bentonite alternative.
The technique uses magnetic nanoparticles – nanometre-scale particles that can be moved around using magnetic fields. Different coatings can be placed on these particles that allow them to bind to different compounds. In a recently published AWRI study, a coating designed to specifically bind haze-forming wine proteins was used. The coated particles were placed in heat-unstable wine, where the proteins bound to the nanoparticles’ surfaces. The particles were then able to be removed from the wine using a magnet.
Testing of the wine following the treatment found that the haze-forming proteins were removed, even from wines with very high protein content. Other components, such as wine phenolics, were unaffected. This technique therefore has potential to be used in the wine industry as an alternative to bentonite fining or could find applications in other areas such as water treatment or biotechnology.
Mierczynska-Vasilev, A., Boyer, P., Vasilev, K., Smith, P.A. A novel technology for the rapid, selective, magnetic removal of pathogenesis-related proteins from wines. Food Chem. 232: 508-514.; 2017.