Extraction method of lavender oil
After crushing 50 g of lavender, steam distillation, the distillate was extracted with ethanol, the filtrate was dried with anhydrous Na2SO4, the ethanol was evaporated, and the weight was weighed.
Put 50g of 20 mesh lavender powder into the extractor, add water for distillation, collect the essential oil and weigh it to 0.515g, the yield is 1.03%.
The microwave extraction method uses n-hexane as the extraction solvent, accurately weighs 20 g of lavender, uses microwave-assisted extraction of lavender oil, and distills the resulting extract under reduced pressure, dried with anhydrous Na2SO4, and weighed.
The microwave power is 700W, the solvent consumption is 200mL, the radiation time is 350s and the detergent is 40mL.
Under these conditions three additional verification experiments, the corresponding essential oil yields were 2.60%, 2.57%, and 2.64%.
Mothed of supercritical CO2 extraction for lavender oil
The best extraction process of lavender essential oil with supercritical CO is extraction time 160min, extraction pressure 20MPa, flow 15L/h, and extraction temperature 45℃. In three additional experiments under these conditions, the yields of the corresponding essential oils were 4.39%, 4.63%, and 4.7%, with an average value of 4.497%.
Ultrasonic assisted solvent extraction
The particle size of the material is the main factor that affects the oil yield, followed by the ultrasonic time, and the material-to-liquid ratio has no obvious influence on the oil yield;
The optimal extraction process conditions for ultrasonic-assisted solvent extraction of lavender oil are:
The particle size of the material is 40 mesh, the material-liquid ratio is 1:12, and the ultrasonic time is 30min. At this time, the oil yield is the highest.
Microwave extraction, ultrasonic assisted extraction and supercritical CO2 fluid extraction are better than traditional extraction methods in terms of the yield of essential oils. However, the quality of essential oils extracted by microwave and ultrasonic assisted solvent extraction is not good. The residual solvent n-hexane is not easy to remove, so it has a slight peculiar smell .
The essential oil extracted by supercritical CO2 fluid has good appearance quality, the highest yield, and does not have the problem of residual organic solvents. This method is conducive to the retention of the effective ingredients of lavender essential oil. It is suitable for extracting lavender essential oil and is the best technology for extracting lavender essential oil.
Comparison of three extraction methods of lavender oil
Supercritical CO2 fluid extraction
The optimal process conditions for supercritical CO2 fluid extraction are: extraction time 160min, extraction pressure 20MPa, flow rate 15I/h, extraction temperature 45°C, under these conditions, the essential oil yield is 4.497%.
The optimal technological conditions for microwave extraction are: using n-hexane as the extractant, microwave power 700W, solvent consumption 200mL, radiation time 350s and detergent consumption 40mL, the yield under these conditions is 2.60%.
Ultrasonic assisted solvent extraction
The best process conditions for ultrasonic-assisted solvent extraction are: the material particle size is 40 mesh, the material-to-liquid ratio is 1:12, the ultrasonic time is 30 minutes, and the yield is 1.09% under these conditions.
Comprehensive considerations, supercritical CO, fluid extraction technology is the best choice for extracting lavender essential oil.
Microwave and ultrasonic-assisted solvent extraction and supercritical CO: The yield of lavender essential oil in fluid extraction is better than traditional extraction methods, but in terms of quality, the quality of the essential oil from microwave and ultrasonic-assisted solvent extraction is poor due to the removal of residual organic solvents. The essential oil extracted by supercritical CO2 fluid has the best quality and yield. Therefore, supercritical CO2 fluid extraction technology is the preferred technology for extracting lavender essential oil.