Innovative Non-Releasing Polyphenol Systems as a New Strategy Against Rosé Wine Oxidation

Rosé wines are particularly prone to oxidative degradation due to their low polyphenolic content, which compromises color stability and shelf life. This study introduces an innovative strategy to enhance wine oxidative stability through the immobilization of grape must polyphenols on glutaraldehyde-crosslinked chitosan beads. Polyphenols were simultaneously extracted and immobilized, achieving an immobilization efficiency of up to 74.5% for total polyphenols and over 67% for total anthocyanins. Among all formulations, beads crosslinked with 1% glutaraldehyde (polyphenol-functionalized beads [PFB]-C4) showed the highest bioactive retention and were selected for application in rosé wine subjected to accelerated oxidative stress (60°C). No detectable release of polyphenols was observed in model wine solutions, confirming the stability of the immobilization system. Wines treated with PFB-C4 exhibited significantly higher Fe2+ stability and improved color preservation compared to the control. Specifically, a* and b* values remained significantly higher (p < 0.05), and chroma (C*) ranged between 28.86 ± 0.43 and 31.79 ± 0.02, indicating greater color intensity (CT) and saturation. Moreover, CI was better retained, whereas tonality (T) remained lower, reflecting reduced browning and pigment degradation. These findings demonstrate that immobilized polyphenols act as both antioxidants and chelating agents, modulating iron redox balance and limiting Fe3+ formation. This study provides the first evidence of using immobilized grape polyphenols as a natural, reusable, and regulation-compliant antioxidant strategy to preserve rosé wine color and stability. The immobilization process provides a sustainable and reusable alternative to sulfur dioxide use, although further optimization is required to improve scalability and standardize polyphenol loading efficiency.