In our country, jasmine plants are highly valued for their economic potential. Jasmine flowers are the primary ingredient used in the fragrance infusion technology for tea processing. However, due to the contrasting harvesting times of jasmine flowers and tea plants, the use of jasmine for tea infusion technology has encountered certain challenges. To overcome these seasonal difficulties and enhance the effectiveness of jasmine cultivation in our country, researchers have proposed technical solutions involving industrial technology and equipment for extracting jasmine essential oil to serve the tea infusion industry. This solution aims to encourage the population to cultivate jasmine on a larger scale in our country, while also contributing to the growth of the essential oil production sector in general and jasmine essential oil in particular. This research project was honored with a VIFOTEC encouragement award in 2003.
The first aspect of the solution is to identify a method for extracting natural jasmine essential oil with high yield while preserving the characteristic fragrance of fresh jasmine flowers.
The second aspect of the solution involves researching and developing technological equipment to extract jasmine essential oil with high yield, maintaining the natural jasmine scent, ensuring the purity of the extracted oil, and reducing production costs.
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Sambac Jasmine |
To ensure that the technical solution progresses beyond the laboratory stage and is implemented in practical production, researchers conducted trials using locally available raw materials for solvents to avoid the use of costly imported solvents and studied the development of suitable industrial equipment for the production of jasmine essential oil, particularly for the Sambac variety in our country.
Currently, various methods are used worldwide to extract essential oils from flowers. In France and Bulgaria, for instance, non-volatile solvents (such as purified lard) are used to absorb floral scents. The drawback of this method is that the process of separating the scent from the solvent occurs at high temperatures, which can lead to the degradation of aromatic compounds and incomplete extraction. Additionally, this method requires a considerable amount of space for equipment installation.
The steam distillation method uses steam generated from a boiler to pass through trays containing flowers, thereby capturing the fragrance along with the steam, which is then separated from the steam through distillation. The limitation of this method is that the essential oil yield is low, and the oil lacks the characteristic scent of natural flowers due to the boiling point of water being significantly higher than the temperature range of the flower’s aromatic compounds.
The extraction method using ether solvents has a drawback in that the fragrance extraction is not complete due to the wide boiling point range of ether, which spans from 30°C to 90°C, making it difficult to separate the solvent from the essential oil. Furthermore, the temperature control devices in the system are challenging to program due to the broad boiling point range.
In Vietnam, researchers have implemented the following method for extracting jasmine essential oil:
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Tea Leaves |
Jasmine flowers and the solvent are placed in a reaction vessel at a ratio of one part flowers to three parts solvent. The mixture is stirred continuously for a duration of 12 to 32 hours (depending on capacity and season) at a temperature of 30 – 32°C. Due to the agitation pressure, the cells containing essential oil are ruptured and dissolved in the solvent, forming an extract. After a low-pressure distillation process to separate the solvent from the essential oil, crude essential oil (flower wax) is obtained. The flower wax is then dissolved in ethanol. Following filtration and low-pressure distillation to separate the ethanol from the essential oil, pure jasmine essential oil is obtained.
To meet production demands that align with the current conditions in Vietnam, researchers designed and built industrial equipment with a capacity of 0.5 tons of flowers per batch. The equipment (including flower mixing devices, low-pressure distillation systems, and cooling systems…) is designed for continuous, closed-loop operation. This design method maximizes the preservation of the aromatic compounds in jasmine essential oil, ensuring the natural fragrance of the flowers is retained.
The natural jasmine essential oil extraction method achieves a high extraction efficiency of over 99% while preserving the characteristic aroma of fresh jasmine flowers. This method has been successfully tested on jasmine-scented tea products and has been applied in practical production, benefiting society. It also serves as an encouragement for the community to expand jasmine cultivation in our country.
Nguyễn Hương
