Abstract 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 of Pogostemon 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°C (T3), 40°C (T4), 50°C (T5) and 60°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°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.

中文翻译：

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新鲜广藿香（Pogostemon cablin）叶不同干燥方法的标准化，以提高精油产量和质量

摘要 广藿香（Pogostemon cablin）是喜荫植物，其干叶用于提取精油，用于优质香水。本研究的目的是找出在控制温度下采用各种干燥方法对广藿香精油产量和质量的影响。收集注册品种 Pogostemon cablin 'Jor Lab P-1" 的新鲜植物叶子用于实验研究。新鲜广藿香在不同的阳光直射条件 (T1)、阴干条件 (T2) 和烘箱下干燥在不同温度范围 [30°C (T3)、40°C (T4)、50°C (T5) 和 60°C (T6)] 的条件下。采用蒸汽蒸馏工艺从每个处理过的样品中提取精油。发现精油产量在 T1 样品中最低 (1.40 %)，其次是 T2 (1.80 %)。发现样品 T4 的挥发油含量 (2.80%) 在所采用的各种温度范围中是最好的。将草本植物暴露在超过 40°C 最佳温度的温度范围内会导致精油产量下降。所有处理过的样品的精油也通过 GC/MS 分析了不同的干燥方法，结果表明不同处理的所有研究精油中的主要成分是广藿香醇。广藿香酒精含量最高的是 T1 精油 (36.63%)，最低的是 T2 (30.33%)。