Oxygen Dynamics in Model Wine Systems Containing Ascorbic Acid and Inactive Dry Yeasts: A Study Using VisiSens 2D™ Imaging

Background Oxygen ingress and distribution significantly impact wine quality, affecting oxidation, colour stability, and aroma development. Quantifying effective oxygen diffusion coefficients (D eff ) in wine-like matrices is essential for optimizing storage conditions and antioxidant strategies. Objective Ascorbic acid and inactive dry yeasts are among the approaches used to limit oxygen ingress in wine systems. This work evaluates these strategies by measuring D eff in synthetic wine matrices containing ascorbic acid or inactive dry yeasts (Longevity® and Glutastar®), and by assessing the VisiSens 2D imaging system as a non-intrusive tool for spatiotemporal monitoring of oxygen diffusion dynamics. Methods Synthetic wines (10% ethanol, pH 3.5, Fe(III) 3 ppm, Cu(II) 0.3 ppm, potassium tartrate) were prepared with either ascorbic acid or inactivated yeasts. Samples were placed in sealed bottles with a sensor foil strip spanning the liquid and headspace. The VisiSens 2D system recorded oxygen saturation at multiple depths over time at 20 ± 1 °C. D eff maps were generated from measured oxygen profiles in liquid and gas phases. Results Ascorbic acid caused rapid, uniform depletion of dissolved O₂ and suppressed diffusion, especially near the air–liquid interface. Inactive yeasts reduced oxygen more gradually and exhibited spatial heterogeneity: Longevity® showed delayed localized diffusion; Glutastar® produced complex diffusion peaks mid-depth. Headspace diffusion was similarly constrained under antioxidant treatments. Gas–liquid oxygen transfer rates mirrored these patterns. Conclusions The VisiSens 2D imaging system effectively quantifies oxygen diffusion and gradients. Inactivated dry yeasts offer a promising, more gradual alternative to chemical antioxidants for managing oxygen in wine-like systems, particularly relevant for low-sulfite or natural wine production.