Traditional vs Bioprotection: Comparative Evaluation of Four Metschnikowia pulcherrima Strains in fermentation

Growing market pressure and consumer concerns over food additives have driven the demand for low-sulfur or sulfur-free wines. Due to the limitations of alternative preservation methods (high cost and efficacy constraints), biological protection has recently emerged as a promising approach. This study compared the protective efficacy of four Metschnikowia pulcherrima strains (Mp346, Mp29, Mp54, Mp57) and Saccharomyces cerevisiae with glutathione (20 g/hL) and S. cerevisiae with sulfur dioxide (50 mg/L) for wine preservation. For each treatment group, three independent fermentation replicates (n=3) were carried out using 200 mL of grape juice in 250 mL wide-mouth ISO bottles, with daily monitoring of dissolved oxygen and redox potential (mV).

Through controlled fermentations with continuous monitoring, the M. pulcherrima strains demonstrated superior oxygen management, maintaining must under consistently lower oxidative stress throughout fermentation compared to chemical alternatives, and the sensory analysis revealed that M. pulcherrima conferred pronounced floral characteristics. These results demonstrate that non-Saccharomycetes yeasts with bioprotective traits like M. pulcherrima outperform traditional methods in both oxidative stability and sensory profile, offering a viable strategy for sustainable winemaking.