The Impact of Drying Methods on Product Quality of Rosmarinus officinalis L.

Abstract

This study was conducted to evaluate the effects of different drying methods (shade drying, sun drying and oven drying at 40°C) on essential oil content, composition and color quality of rosemary (Rosmarinus officinalis L.). The essential oil content was obtained by hydro-distillation of dried plants, and were analyzed by GC-MS. The results showed that different drying methods had no significant effects on essential oil content, but essential oil constituents and percentage affected by drying methods as well. Camphor, (between 27.57 and 29.15%), 1.8 cineol (between 17.62 and 9.39%), borneol (11.25-12.37%) and linalool (between 7.30 and 8.18%) were the major essential oil compounds of different drying methods. In total regarding the essential oil composition, oven drying method can be recommended as the appropriate procedure for major constituents of rosemary essential oil. In this study, Lightness (L*), greenness (a*), and yellowness (b*) of dried leaves were also evaluated. Drying methods affected the color quality of the herb.