Standardization of Different Drying Methods of Fresh Patchouli (Pogostemon cablin) Leaves for High Essential Oil Yield and Quality

Patchouli (Pogostemon cablin) is shade loving plant and the shade dried leaves are used for essential oil extraction which is used in high-quality perfumery. The present study is aimed to find the effects on the yield and quality of essential oil of patchouli by various drying methods employed with controlled temperature. Fresh plant leaves of the registered variety ofPogostemon cablin'Jor Lab P-1" were collected for the experimental study. Fresh patchouli herbage was dried under different conditions of direct sunlight exposure(T1), under shade drying condition (T2) and oven drying condition with varying temperature ranges [30 degrees C (T3), 40 degrees C (T4), 50 degrees C (T5) and 60 degrees C (T6)]. The steam distillation process was employed for extracting essential oil from each treated sample. The essential oil yield was found to be lowest in the T1 sample (1.40 %) followed by T2 (1.80 %). The volatile oil content of sample T4 (2.80 %) was found to be the best among the various temperature ranges employed. The exposure of the herbage to a temperature range beyond the optimal temperature of 40 degrees C thus leads to a decrease in essential oil yield. The essential oils of all the treated samples were also analyzed through GC/MS for the different drying methods which yielded that the major component was patchouli alcohol in all the studied essential oil of the different treatments. The highest patchouli alcohol content was present in the T1 essential oil (36.63 %) and the least was recorded in T2 (30.33 %). Thus the standardized methods for drying of patchouli should be employed for efficient and maximum essential oil extraction from the dried leaves.