Drying Method Affects Essential Oil Content and Composition of Basil (Ocimum basilicum L.)

This study was conducted to evaluate the effects of different drying methods (shade drying, sun drying and oven drying at 40 degrees C and 60 degrees C) on essential oil content and composition of common basil (Ocimum basilicum L.). Flowering aerial parts of basil plants were dried under different methods until constant weight. Volatile oil content and composition of plants were determined by Clevenger type apparatus and GC-MS method respectively. The results showed that different drying methods had significant effects on essential oil content as: shade drying (0.9 %) > oven drying at 40 degrees C (0.8 %) > sun drying (0.5 %) > oven drying at 60 degrees C (0.4 %) respectively. Essential oil constituents number and proportional percentage affected by drying methods as well. Estragol (11.3-51.3 %), menthone (0.4-33.1 %), linalool (1.7-7.8 %), phytol (0.1-6.1 %), methyl eugenal (1-4.2 %), trans-alpha-bergamotene (0.7-3.9 %) and trans-beta-farnesene (1.1-3.9 %) were the common major volatile oil compounds of different drying methods. Menthol (6.1 %), isoneomathol (7.5 %), menthyl acetate (5.6 %), piperitone (3.7 %) and limonene (1.5 %) were the major components of shade dried plants. alpha-Cadinol (2.9-21.1 %) and phytol had appreciable amounts under oven drying conditions. Delta-cadinene and gamma-cadinene were exclusive of sun drying and 60 degrees C oven dried plants respectively. In total regarding the essential oil content and composition, traditional shade drying method was distinguished as the appropriate procedure for sweet basil drying.