Holistic and Sustainable Approach for Recycling and Valorization of Polyvinylpolypyrrolidone Used in Wine Fining

Polyvinylpolypyrrolidone (PVPP) is a synthetic water-insoluble polymer widely used as fining agent in the wine industry for removing low-molecular-weight phenolics. Used PVPP, estimated in 2014 of 1037 tons, ends up in the municipal wastewater treatment plants with a detrimental environmental impact. Recycling of PVPP for obtaining fully reusable PVPP and wine phenolic concentrates for the food, cosmetic, and pharmaceutical industries would increase the sustainability of its use. An ammoniacal solution of ethanol allows one to desorb with high recoveries (average 73%) the PVPP adsorbed phenolics with yields ranging from 2.82 to 10.80 g/kg of wet PVPP, depending on the wine. Extracts were nearly pure concerning the phenolics abundance (>89%), without need of further purification. The performance of the recycled PVPP for white wine fining was not significantly different from that of the new PVPP, which can be recycled at least four times without loss of fining performance and allow a good recovery of adsorbed phenolics to be maintained. Results obtained in this work show that by using a simple, cheap, and eco-friendly recycling strategy, it is possible to reuse PVPP for wine fining, providing a cleaner winemaking process and additionally obtain wine phenolic concentrates with high purity, antioxidant, and bioactivity, valuable for other industries.