TiO2-Coated Glass Spheres as an Advanced Material for Wine Protein Stabilisation

Abstract

Wine protein stabilisation, i.e., the removal of pathogenesis-related proteins (PRPs), is a step in the white wine fining process. Winemakers use bentonite for this purpose. However, its use has drawbacks due to the production of voluminous waste, wine loss during racking, and decrease in wine quality due to the adsorption of colour components and aroma. New materials for stabilising wine proteins are the object of this study. In this context, an engineered production process for TiO₂-coated glass spheres and a use protocol were developed as an alternative to bentonite treatment, providing relevant information for process scalability. This paper describes the wine protein adsorption capability of a patent-based, innovative material consisting of thin layers of TiO₂ nanoparticles supported on food-grade glass spheres, to be used for the protein stabilisation of wine in a flow process. Protein removal was assessed by the heat test and Pierce’s test on unstable wines. As a safety-related criterion, the amount of TiO₂ released during use was quantified by ICP–OES. The possibility of regenerating the material during use and recycling it at the end of life was also investigated, together with a preliminary cost assessment. Overall, the proposed solution follows a “safe and sustainable by design” (SSbD) approach, matching functionality (selectivity for proteins and heavy metals), safety, cost and recyclability criteria.