The Impact Of Different Fining Agents On The Macromolecular Composition And Stability Of Sangiovese And Montepulciano Italian Red Wines

This study investigated the impact of five commercial enological treatments on the macromolecular composition, colloidal properties and stability of two Italian red wines: Sangiovese and Montepulciano. Among the products tested, one (Treatment A) functioned as a true fining agent, while the others (Treatments B–E) were stabilizing or mouthfeel-enhancing additives, including gum arabic, mannoproteins, and oak wood tannins. Each treatment was applied to both wine varieties, with samples collected immediately after addition (T0) and after three months of storage (T3). A multi-parameter analytical approach was used to assess changes in turbidity, heat stability, total phenolic content (Folin–Ciocalteu assay), polysaccharide concentration (HRSEC), nanoparticle tracking (NTA), and overall colloid content. The aim was to evaluate how different additive compositions interact with the wine matrix, and whether grape variety influences the outcomes. The results revealed clear differences in treatment performance. Treatments A and D proved to be the most technically effective. Treatment A delivered consistent protein stabilization and moderate clarification particularly in Montepulciano, while Treatment D stood out for its ability to enhance heat stability and structural richness, especially in Sangiovese. Treatment E, although subtler in its immediate effects, showed signs of oxidative protection and long-term structural support, making it well-suited for wines destined for aging. Treatments B and C showed more selective effects: Treatment C improved mouthfeel and colloidal complexity but was associated with increased turbidity over time, while Treatment B was the least effective from a stabilization standpoint, offering limited improvements and showing inconsistent performance across key parameters. Although this project includes additional sampling points (T6 and T12), the T0–T3 data already provide valuable insights into the short-term behavior of red wines following additive application. The findings emphasize the importance of tailoring enological treatments to both the desired wine style and the specific variety, balancing stability and sensory expression.