Cristina Medina-Plaza, Aubrey DuBois, Elizabeth Tomasino, and Anita Oberholster*
*University of California, Davis, Department of Viticulture and Enology, 595 Hilgard Ln, Davis, CA 95616 (aoberholster@ucdavis.edu)

Bottled wine can be exposed to UV-visible light for relatively long periods of time in retail stores, restaurants, or domestic settings. Exposure to light and elevated temperature can decrease wine quality by causing color change and production of off-odors. The impact of bottle color, light exposure, and temperature on rosé wine ageability and quality was studied. Rosé wines with different organoleptic characteristics (color, phenolic, sugar, and alcohol content) were bottled in clear or green bottles and stored at room temperature (22°C) or cellar temperature (12°C) under
three different light conditions (darkness, fluorescent bulb, and cool white LED bulb). Wines were analyzed after 0, 3, and 6 months of storage. The color and phenolic composition were determined by RP-HPLC and spectrophotometric analysis. Potential changes in aroma were determined through volatile screening of the wines using SPME-GC-MS. Spectrophotometric analysis showed that color intensity decreased over time. The combination of light type and bottle color had the greatest impact on color (CIELAB color space). For example, the color intensity of wines stored in clear bottles decreased more than those stored in green bottles. Under same temperature and bottle conditions, fluorescent light had a larger impact than LED. Wines stored in the dark, independent of bottle type and temperature, were not affected. Higher temperature and/or clear glass increased the percentage of yellow and decreased the percentage of red color in the wines, potentially due to oxidation. There were significant changes in aroma profiles between the starting wines and the different time points. In this case, bottle color had a smaller impact than storage temperature. Overall, while all variables studied affected rosé wine aging significantly, higher temperature in combination with clear glass bottles under fluorescent light was most detrimental to rosé wine aging.

Funding Support: Lyon-Cisneros Family Research Fund