Production Rate Analysis of Citronella Essential Oil Using Distillation Method

. Semoyo is one of the districts located in Gunungkidul Regency. The community engages in the cultivation of traditional medicinal plants. One of the most widely cultivated plants is citronella. The community produces a significant amount of citronella, but it has yet to be processed into high-value economic products. Currently, citronella has emerged as a promising commodity because it can be used as a raw material to produce essential oil. The production of citronella essential oil is carried out through steam-hydro distillation. This research aims to test the distillation characteristics to determine the potential production of citronella essential oil and to decide the rate and capacity of essential oil production using citronella as the raw material. Based on the test results, the optimal duration for the distillation process of 2,000 grams of citronella was 60 minutes, with a maximum duration of 90 minutes. The yield of citronella essential oil obtained from this test was 0.414%. The resulting citronella essential oil had a density of 0.920 grams/mL, a clear appearance, a distinctive lemongrass aroma, and a light-yellow color. These criteria meet the SNI 3953:2019 for citronella essential oil.


Introduction
Gunungkidul is one of the regencies in the Special Region of Yogyakarta Province, with a total area of 1,485.36km 2 [1].Gunungkidul Regency has various potential attractions, including a cultivation of traditional medicinal plants, or known as "toga" in Indonesian.Semoyo is one of the regions in Gunungkidul located in Patuk District, covering an area of 575,000 hectares and has an elevation of 350 meters above the sea level [2].The environmental conditions in this area are suitable for traditional medical plant cultivation, so many local communities utilize empty land to grow those plants.One commonly cultivated traditional medicinal plant in Gunungkidul is citronella.The local community produces a plentiful supply of citronella plants, but it has yet to be processed into high-value economic products.The citronella plants obtained are only sold in their wet condition which are then used as a kitchen spice and herbal drink ingredient.
Currently, citronella plants have become an excellent commodity because it can be used as a raw material to produce essential oil.Essential oil is one of Indonesian export commodities that has the potential to continue competing in the international market.The main compounds found in citronella essential oil are citronellal, citronellol, and geraniol [3], [4].These three compounds determine the pleasant aroma of the resulting oil products.Citronella essential oil is widely used in various industries, including food, perfumes, aromatherapy, cosmetics, and herbal medicine [5].The selling price of pure citronella essential oil ranges from Rp 300,000.00 to Rp 500,000.00 per liter.This price is much higher compared to selling citronella plants directly.
The production of citronella essential oil is typically carried out through distillation.Distillation is a method of separating components of a mixture, whether solid or liquid, based on their differences in boiling points [6].In the distillation process, the oil in the citronella plant evaporates with steam and then is separated through condensation [7].There are three common distillation methods: water distillation, steam distillation, and steam-hydro distillation [8].Distillation is a method that yields better quality results compared to pressing and leaching processes [9].Furthermore, distillation is chosen because the required equipment is simple and can be easily carried out by the community.According to the Research and Development Center for Plantation [10], the average yield of citronella essential oil obtained using distillation is approximately 0.6% to 1.2%.
Based on the above data, it is necessary to conduct distillation characteristic testing to determine the potential for citronella essential oil production using the steam-hydro distillation method.The research aims to determine the rate and capacity of essential oil production using citronella as a raw material, thereby potentially increasing the economic value of citronella.This can be a step towards improving and enhancing the local economy of Semoyo.

Materials
This research utilized citronella plants as the raw material in cultivating traditional medicinal plants in Semoyo, Patuk, Gunungkidul, Special Region of Yogyakarta.

Apparatus
The research used steam-hydro distillation equipment, including a steam boiler, condenser, refrigerator, thermocouple, and data logger.The arrangement of the steam-hydro distillation apparatus is shown in Fig. 1.

Procedures
This research utilized the steam-hydro distillation method to obtain citronella essential oil.The steam-hydro distillation method was chosen in this research because it required a relatively shorter distillation time and yielded more essential oil with better quality compared to water distillation or boiling [12].The steam-hydro distillation method was conducted using water as the steam generator.The citronella plant, which would be distilled for its oil, was cut into smaller pieces to facilitate the process.The distillation of citronella essential oil was carried out for 3 hours at a constant temperature.In the distillation process, the oil contained in the citronella plant evaporated along with steam, and then it was separated through condensation.The production of essential oil was measured periodically every 10 minutes.Oil and water were separated from the condensed mixture by allowing it to settle for a moment.The data on essential oil production were processed to analyze the rate and capacity of production.The resulting citronella essential oil was subjected to organoleptic observation, including physical appearance, color, and aroma.Determining the density of the citronella essential oil product was also conducted.The observed criteria were compared with SNI 3953:2019 to assess the quality of citronella essential oil.

Equation and Mathematics
The analysis of the oil reduction rate is conducted using the following equation [13]: The above equation calculated the oil content at the initial and final phases.In the initial phase, the reduction of oil content occurred steadily and continuously.When the equilibrium oil content was reached, the rate of oil reduction would decrease.In this phase, the oil content in the sample was calculated using an equation derived from the oil content ratio equation.

Results and Discussion
The distillation testing of the citronella plant for 3 hours resulted in 9 mL of essential oil product.This test used a wilted citronella plant cut into smaller pieces for easier handling.The citronella plant mass used as the essential oil raw material was 2,000 grams.The data on the reduction of citronella plant mass during the distillation process are shown in Fig. 2. Fig. 2 illustrates the reduction in citronella plant mass during the 3 hours of testing.The data indicate no further decrease in citronella plant mass after the 90 th minute.In the initial phase of the distillation process, there is a rapid and constant reduction in mass.This is indicated by the constant "k" value, which equals to 0.184.The constant "k" value is obtained from the gradient of the mass reduction curve from the 30 th to the 60 th minute.Fig. 3 shows the value of the constant "k" in the initial phase of the distillation process.After the 60 th minute, the citronella plant mass reduction rate decreases due to the reduction in oil content in the sample.By the 100 th minute, the mass of the citronella plant no longer decreases, and no more essential oil is produced.Fig. 4 shows the value of the constant "m" in the final phase of the distillation process.The obtained value of the constant "m" is 0.046.This value indicates that since the 70 th minute, essential oil production is no longer significant although some essential oil is still produced until the 90 th minute.The physical property testing of the essential oil product reveals a density value of 0.920 grams/mL, a clear appearance, a distinctive lemongrass aroma, and a light-yellow color.These physical properties meet the requirements of SNI 3953:2019 for citronella essential oil.

Conclusion
From the distillation testing of citronella essential oil using the steam-hydro distillation method for 3 hours, the following results are obtained: 1.The optimal duration for the distillation process of 2,000 grams of citronella plant is 60 minutes based on the constant "k" calculation.2. The maximum duration for the distillation process of 2,000 grams of citronella plant is 90 minutes.3. The yield of citronella essential oil obtained in this testing is 0.414%.4. The quality of the citronella essential oil produced meets the requirements of SNI 3953:2019 in terms of density, appearance, color, and aroma.