Daniela Silva1 , Fernando N. Salazar2 , Francisco López3 , Néstor Escalona4 , José R. Pérez1
1 Laboratorio de extracción de compuestos de alto valor, Departamento de Ingeniería Química y Bioprocesos, Pontificia Universidad Católica de Chile, Santiago, Chile
2 Laboratorio de Fermentaciones Industriales, Escuela de Alimentos, Facultad de Ciencias Agronómicas y de los Alimentos, Pontificia Universidad Católica de Valparaíso, Chile
3 Unitat d’Enologia del CeRTA (Generalitat de Catalunya), Departament d’Enginyeria Química, Facultat d’Enologia, Universitat Rovira i Virgili, España
4 Departamento de Ingeniería Química y Bioprocesos, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
Email contact: dcsilva1[@]uc.cl
A common problem in wineries is haze formation after bottling, mainly caused by unstable proteins present in white wine. The most used material to eliminate these proteins is bentonite. This material effectively removes proteins, but it is very harmful to white wine since it removes all kinds of proteins and other essential compounds from wine. Zirconium oxide (ZrO2) has been shown to remove the proteins responsible for haze selectively, but ZrO2 must be modified to increase the active surface area that adsorbs the proteins. This work aims to use zirconium oxide properties to produce a porous material coated on the surface by a new impregnation technology such as atomic layer deposition (ALD), which is highly active and allows the selective removal of haze-causing proteins from white wine. Zirconium oxide is deposited on 6 mm alumina spheres by the ALD method. As a result, two modified materials (MM) are obtained and are compared with pure zirconium (ZP) and the control wine. Batch and continuous experiments are carried out, subsequently analysed for total protein content by Bradford and polysaccharide and protein content by HPLC. Preliminary results indicate that the spheres remove 10-20% of total proteins from white wine, where the content of proteins <25 kDa decreases and proteins of higher molecular weight are not affected. Pure zirconium in 3 mm discs removes twice as much protein as MM. However, zirconium content in MM is in the order of ~1% and has a lower surface area than ZP is 100% zirconium, but it has a higher active surface area. The polysaccharide content is slightly reduced, but pure zirconium removes more than MM. Therefore, we can conclude that there is a selective reduction of proteins, but this is not enough; this may be due to two aspects: the surface area of pure zirconium is higher than the modified material, and the content is also lower. Therefore, to improve the protein removal with the modified materials, it is proposed to increase the active surface area reducing the spheres' size from the original 6 mm to 2-4 mm.
Salazar, F. N., Zamora, F., Canals, J. M., & Lopez, F. (2010). Protein stabilisation in sparkling base wine using zirconia and bentonite: Influence on the foam parameters and protein fractions. Journal International des Sciences de la Vigne et du Vin, special issue Macrowine., 51–58.
Salazar, F. N., Achaerandio, I., Labbé, M. A., Güell, C., & López, F. (2006). Comparative study of protein stabilisation in white wine using zirconia and bentonite: Physicochemical and wine sensory analysis. Journal of Agricultural and Food Chemistry, 54(26), 9955–9958. https://doi.org/10.1021/jf062632w
Pashova, V., Güell, C., & López, F. (2004). White Wine Continuous Protein Stabilization by Packed Column. Journal of Agricultural and Food Chemistry, 52(6), 1558–1563. https://doi.org/10.1021/jf034966g
Marangon, M., Lucchetta, M., & Waters, E. J. (2011). Protein stabilisation of white wines using zirconium dioxide enclosed in a metallic cage. Australian Journal of Grape and Wine Research, 17(1), 28–35. https://doi.org/10.1111/j.1755-0238.2010.00112.x