Rosé is leading the fastest growth wine category which hit a 40% increase since 2002. France accounts for over a third (34%) of global consumption followed by the US at 16%. The majority of rosé wines are bottled in clear bottles. There are a range of factors that impact the selection of bottle colour for wine storage, but consumer’s acceptance seems to be one factor where market forces drive the use of lighter colored glass bottles over dark green, brown or blue glass. Post-bottling storage is also a critical phase for rosé wine. Bottled wine can be exposed to UV-visible light and temperature fluctuations for relatively long periods of time in retail stores, restaurants and domestic settings, resulting in degradation with colour and aroma changes. This research studied the impact of bottle colour, light exposure and temperature on rosé wine quality.
Four rosé wines with different organoleptic characteristics and chemical composition (colour, phenolic, sugar and alcohol content) were bottled in clear and green bottles and stored under three different light conditions (darkness, fluorescent bulb and cool white LED bulb) at cellar (15°C) and room temperature (20°C). Colour, basic chemical analysis, aroma profile, phenolics and reductive compounds were determined after 0, 3 and 6 months of storage. The colour and phenolic composition were determined by spectrophotometric analysis and RP-HPLC. Potential changes in aroma were determined through volatile screening of the wines using SPME-GC-MS. Reductive compounds were also determined by SPME-GC-MS.
Changes in wines were detectable after 3 months and more noticeable after 6 months of storage. Basic chemical analysis showed a decrease in free and total SO2 for all the samples analyzed with the largest impact found on the samples stored under fluorescent light. Regarding color, a decrease in intensity was found in the wines stored under both light conditions over time, particularly those in clear bottles. An increase in the percentage of yellow and a decrease in the percentage of red was significant in the wines stored at 20°C under fluorescent light and more pronounced in the wines with lighter color/lower phenolic content. This may be due to oxidation reactions occurring under these conditions. Wines stored in the dark showed no significant impact on the colour. There results were supported by RP-HPLC data, showing an increase in polymeric phenols and pigments and a decrease in monomeric anthocyanins. For aroma profiles, significant changes were found between the starting wines and the different time points. When focusing on aroma only, bottle colour showed a smaller impact than storage temperature. Overall, all variables studied impacted rosé wine aging significantly. However, higher temperature in combination with clear glass bottles under fluorescent light were the most detrimental to rosé wine aging compared to low temperature and darkness that showed the smallest impact.
Authors: Cristina Medina-Plaza – University of California, Davis, Aubrey Dubois- Oregon State University Elisabeth Tomasino – Oregon State University Anita Oberholster – University of California, Davis
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