Investigating the Quantitative and Qualitative Changes of Lemongrass (Cymbopogon citratus) Essential oil in Response to Drying Methods

Introduction Factors such as plant development stage, environmental conditions, genetic variation, extraction methods, and drying process influence the chemical diversity of essential oils. Preserving quality is vital in the lemongrass plant trade, and drying is critical for maintaining quality for global markets. Purpose This experiment investigated the effect of different drying methods on the quality of the essential oil extracted from the aerial parts of the lemongrass (Cymbopogon citrates). Methods To examine the impact of various drying methods, such as shade drying, sun drying, and oven drying at temperatures of 35 & ring;C and 45 & ring;C, on the lemongrass essential oil content and compounds, this study was carried out using a completely randomized design with four replications. Following the drying process, essential oils were extracted using a Clevenger apparatus, and their quantity and quality were analyzed using GC and GC-Mass instrumentation. Results Shade drying caused a significant decrease in essential oil percentage compared to the other methods. On the other hand, the highest essential oil content (1.15%) was obtained in oven drying at 45 degrees C, while the lowest (0.93%) was obtained in shade drying conditions. The essential oil analysis results showed that different drying methods led to observing 16 compounds, with eight compounds shared across all methods. Geranial and neral were the main compounds in all treatments, making up around 50% and 30% of the essential oil composition respectively. The highest amount of geranial (56.2%) was found in the oven drying at 45 & ring;C, while the lowest amount (48.6%) was observed in the drying oven at 35 & ring;C. Neral was the second dominant compound, with the highest amount (34.7%) in the oven drying at 45 & ring;C and the lowest amount (32.2%) in the sunshine drying. Other compounds, such as 10-epi-gamma-eudesmol, Z-isocitral, myrcene, geraniol, citronellal, and linalool, also showed varying amounts based on the drying method used. This study indicated that lemongrass essential oil compounds are divided into three main groups: oxygenated monoterpenes, monoterpene hydrocarbons, and oxygenated sesquiterpenes. The highest percentage of oxygenated monoterpenes (96.9%) was in samples dried in an oven at 45 & ring;C, with no significant difference from shade-dried and sunshine-dried samples. The lowest content of oxygenated monoterpenes (84.6%) was in samples dried in an oven at 35 & ring;C, significantly lower than other drying methods. For monoterpene hydrocarbons, the highest amount (6.8%) was in shade-dried samples at room temperature, significantly, differing from other treatments. The lowest amount of monoterpene hydrocarbons (1.8%) was in samples dried in an oven at 45 & ring;C, showing a significant difference from other drying methods. Oxygenated sesquiterpenes had the highest amount (4.5%) in plants dried in an oven at 35 & ring;C, significantly differing from other treatments. No significant difference was found among the other drying methods for oxygenated sesquiterpenes. Conclusion Results indicate that the drying method significantly affects the quantitative and qualitative characteristics of lemongrass essential oil, with the best drying method being an oven at 45 degrees C. No previous studies on drying methods' impact on lemongrass essential oil qualities make this study a potential avenue for future research.