Essential Oil Composition of Rosa damascena Mill. Produced With Different Storage Temperatures and Durations

The present study was conducted to investigate the effects of storage and temperature on the quality of Damask rose (Rosa damascena Mill.) flowers in southwestern Iran in 2016 and 2017. Flowers were harvested and distilled immediately or stored at 25 degrees C, 4 degrees C and -20 degrees C for 6, 12, 24, 48 or 96 hours before distillation. Results obtained from GC/MS showed 39 essential oil components, most of which were beta citronellol, nonadecane, geraniol, trans geraniol, heneicosane, heptadecene and pentadecane. The highest (0.054% to 0.055%) and lowest (0.011% to 0.019%) levels of essential oil content were obtained at -20 degrees C x 6 hours and 25 degrees C x 96 hours post-harvesting, respectively. The highest percentage of beta citronellol (36.3 +/- 1.2% to 35.1 +/- 5.5%) was obtained at -20 degrees C x 6 hours post-harvesting. Nonadecane levels increased with increasing storage time, particularly at -20 degrees C x 96 hours post-harvesting (21.1 +/- 0.08% to 16.2 +/- 0.9%). Generally, the levels of most of the essential oil components decreased with increasing storage time, but this loss was avoided with freezing temperatures (-20 degrees C).