Author: Samadhi Chinthana Chandrasekara Chandrasekara Mudiyanselage
Chandrasekara Mudiyanselage, Samadhi Chinthana Chandrasekara, 2025 Exploring alternatives to pvpp for fining phenolic compounds in wines, Flinders University, College of Medicine and Public Health
Terms of Use: This electronic version is (or will be) made publicly available by Flinders University in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. You may use this material for uses permitted under the Copyright Act 1968. If you are the owner of any included third party copyright material and/or you believe that any material has been made available without permission of the copyright owner please contact copyright@flinders.edu.au with the details.
The wine industry is looking to sustainable and environmentally friendly alternatives as a global trend. Polyvinylpolypyrrolidone (PVPP) is a synthetic polymer commonly used to remove phenolic compounds from wine. Due to its plastic-based nature and inability to biodegrade, it is important to find a sustainable and environmentally friendly alternative to replace PVPP. This study identified a range of carbon-based nanomaterials, including graphene (G), activated carbon (AC), carbon nanotubes (CNT), and functionalized carbon nanotubes (OH-CNTs, COOH-CNTs and NH2-CNTs), as potential alternatives to PVPP for removing phenolic compounds from white wines. This study applied an experimental plan with seven fining agents at five concentration levels (200-2,000 mg/L) in Riesling and Chardonnay wines, which were used as a matrix. Scanning electron microscopy (SEM) revealed distinct morphological characteristics for each nanomaterial. Nanoparticle tracking analysis (NTA) proved that various fining agents impacted particle size distribution. UV-Vis spectroscopy demonstrated the effectiveness of reducing total phenolic content at 280 nm absorbance levels, showing that various carbon alternatives were as effective as PVPP. High-performance liquid chromatography (HPLC) analysis of several phenolic compounds, including tyrosyl, caftaric acid, caffeic acid, and quercetin, revealed that AC produced the greatest percentage reduction at the highest concentration (2,000 mg/L). Meanwhile, functionalized CNTs exhibited varying efficiencies based on their surface functionality. The optimal concentration range for using PVPP in white wines is generally 100-800 mg/L. While higher concentrations may enhance phenolic removal, they can also lead to the over-stripping of desirable phenolics, resulting in wines with diminished mouthfeel, reduced aromatic complexity, and imbalanced sensory profiles. Additionally, excessive fining agents use increases production costs, generates more lees, and may complicate subsequent stabilization steps. Therefore, using the minimum effective dose is recommended for balancing wine quality. These results highlighted the importance of selecting fining agents based on the specific objectives of the winemaking process. The results confirmed that, based on effectiveness and cost, carbon-based nanomaterials, especially graphene and carbon nanotubes, are sustainable alternatives to PVPP for use in wine fining. This research provides valuable information for developing a more sustainable approach to winemaking while preserving or improving wine stability and quality.
Keywords: Polyvinylpyrrolidone, PVPP, Multi-walled Carbon Nanotubes, Functionalized Carbon Nanotubes, Wine, Winemaking, SEM, Wine fining, HPLC, Sustainable,
Subject: Biotechnology thesis
Thesis type: Masters
Completed: 2025
School: College of Medicine and Public Health
Supervisor: Dr Agnieszka Mierczynska-Vasilev