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Supercritical CO2 Extraction of Volatile Components from Pandanus Leaf & Squalene

Pandanus leaves

Pandanus fragrant leaves are fresh leaves of Pandanus fragrant, a plant of the genus Pandanus of the family Pandanus. It is also known as pandan leaves, pandanus leaves, and pandan leaves.

Supercritical CO2 Extraction of Pandanus Leaf
Supercritical CO2 Extraction of Pandanus Leaf

Originated in the Maguru Islands, Indonesia, it is mainly distributed in the tropical and subtropical regions of the eastern hemisphere. It is cultivated by the Xinglong Overseas Chinese Farm in Hainan and the South China Tropical Crops Research Institute of Dan County in China.

This genus has various economic uses and is an important economic crop second only to coconut. It is traditionally used in medical treatment and cooking.

Pandanus leaf is used as a traditional Chinese medicine for diuresis, heart strengthening, anti-diabetic, deworming, and skin disease treatment abroad;

Because of its unique aromatic odor, it is often used as a edible spice and is popular in Thailand, Indonesia, Malaysia, the Philippines, Singapore and other countries. Some fresh leaves are added when steaming the rice to make the steamed rice more strong and lasting;

Some use it in the preparation of salads, pancakes, and pastries to increase the flavor of the food, and some use it as a side dish to color. Others use a blender to smash it to make juice and directly use it as a seasoning. It is an important plant resource for both medicine and food.

Although Pandanus sylvestris has been introduced and cultivated in Hainan Province for a long time, there are few reports on its utilization. In order to further develop and study the value of the volatile components of Pandas sylvestris, it is necessary to control the volatile components of Pandanus sylvestris. The supercritical CO2 extraction process has been studied in depth.

Pretreatment of Pandanus leaves

Put fresh Pandanus leaves in a ventilated place to dry naturally, control different water content, crush with a grinder, pass through a No. 2 sieve, and place for later use.

Supercritical CO2 extraction method

Supercritical CO2 extraction process: carbon dioxide cylinder→extraction kettle→separation kettle Ⅰ→separation kettle Ⅱ→separation kettle Ⅲ→carbon dioxide circulation. The crushed Pandanus leaves are put into the extraction kettle, and the extraction kettle, separation kettle and storage tank are heated or cooled respectively.

When the selected temperature is reached, the system is pressurized. When the pressure reaches the selected value, the CO2 gas cylinder is closed, and the cyclic extraction is started, and the constant temperature and pressure are maintained. After the selected time is reached, the separation tank I, Ⅱ, Ⅲ The material is discharged from the discharge port.

The volatile components of Pandanus leaves were collected and the yield was collected, and the content of squalene in the volatile components was determined by high performance liquid chromatography.

The influence of water content on the extraction effect

Accurately weigh 300 g each of Pandanus leaves with different moisture content and put them into a 5L extraction kettle, with a CO2 flow rate of 30 Kg/h, an extraction pressure of 21 MPa, an extraction temperature of 45°C, an extraction time of 60 min, and a separation pressure of 9 MPa, The temperature is 45℃, the pressure of separation Ⅱ and separation kettle Ⅲ is 6 MPa, and the temperature of separation Ⅱ and Ⅲ is 40℃.

With the decrease of moisture content, the yield of volatile components in Pandanus sylvestris and squalene gradually increased, but the moisture content further decreased, and the yields of volatile components and squalene began to decrease. The results showed that, The moisture content is between 11% and 12%, and the extraction rate has a larger value. Therefore, it is more appropriate to control the moisture content of Pandanus leaves at 11%-12%.

The influence of extraction pressure on the extraction effect

Accurately weigh 300 g of the processed Pandanus leaves and put it into a 5 L extraction kettle, extraction time 60 min, CO2 flow rate 30 Kg/h, separation Ⅰ pressure 9 MPa, temperature 45 ℃, separation Ⅱ, separation kettle Ⅲ pressure It is 6 MPa, and the separation temperature of Ⅱ and Ⅲ is 40℃.

At the same temperature, and the extraction pressure is in the range of 15-21 MPa, the yield of volatile components of Pandanus sylvestris and the yield of squalene increase with the increase of pressure.

When the extraction pressure rose to 21 MPa, the pressure continued to increase, and the yield showed a downward trend. For example, when the extraction temperature is 45 ℃, as the extraction pressure rises from 15 MPa to 21 MPa, the yield of volatile components and the yield of squalene both increase rapidly;

When the extraction pressure was increased from 24 MPa to 27 MPa, although the yields of volatile components in Pandanus sylvestris showed an upward trend, the yields were all lower than the yield of 21 MPa, while the yield of squalene showed a downward trend. When the extraction temperature is 55 ℃, as the extraction pressure increases from 15 MPa to 21 MPa, the yield increases slightly;

When the extraction pressure was increased from 24 MPa to 27 MPa, the yield of volatile components in Pandanus sylvestris and the yield of squalene both showed a slight downward trend. Therefore, the optimal extraction pressure is initially determined to be 21 MPa.

The effect of extraction temperature on extraction effect

Accurately weigh 300 g of the processed Pandanus leaves and put it into a 5L extraction kettle. Extraction time
For 60 minutes, the CO2 flow rate is 30 Kg/h, the pressure of separation Ⅰ is 9 MPa, the temperature is 45 ℃, the pressure of separation Ⅱ and separation vessel Ⅲ is 6 MPa, and the temperature of separation Ⅱ and Ⅲ is 40 ℃.

Under the same extraction pressure, the volatile component yield and squalene yield of Pandanus sylvestris and squalene first increase and then decrease with the increase of temperature. When the extraction pressure is 21 MPa and 45℃, the yields of volatile components and squalene of Pandalus sylvestris are The yields are the highest, and when the extraction pressure is 27 MPa, the yield of volatile components in Pandanus sylvestris and the yield of squalene are higher at 40°C.

Therefore, it is preliminarily determined that the optimal extraction temperature is 45°C.

The effect of extraction time on the extraction effect

Accurately weigh 300 g of the processed Pandanus leaves and put it into a 5L extraction kettle, with a CO2 flow rate of 30 Kg/h, an extraction kettle temperature of 45 ℃, separation Ⅰ pressure 15 MPa, temperature 45 ℃, separation Ⅱ pressure 12 MPa, temperature 40 ℃, the pressure of separator III is 6 MPa, and the temperature of separation II and III is 40 ℃.

Within 30 minutes before the start of extraction, the yield of volatile components increased rapidly, but after 60 minutes of extraction, the increase in yield was gradually slow.

In addition, the yield-extraction time curve is different for different extraction pressures; when the extraction pressure is 15 MPa and the extraction time is 60 min, the yield of volatile components is 2.80%.


At a pressure of 21 MPa, if the yield of volatile components is to reach 2.80%, it takes less than 60 min. It can be seen that the higher the extraction pressure, the faster the extraction rate, and the less time it takes to complete the extraction.

The squalene yield-extraction time curve in the volatile components of Pandanus sylvestris also showed a corresponding trend. Therefore, the extraction time is determined to be 60 minutes.

The influence of analytical conditions on the separation effect

Supercritical extraction equipment generally has two separation tanks. By adjusting the separation conditions of the two separation tanks, the extraction material can be finely separated, and the target product can be effectively extracted and separated.

Therefore, this study did not investigate the pressure and temperature of Separator III, and fixed the pressure and temperature of Separator III at 6MPa and 40°C.

Separation Ⅰ Influence of pressure

Accurately weigh 300 g of the processed Pandanus leaves and put it into a 5 L extraction kettle. The extraction pressure
21 MPa, extraction temperature 45 ℃, extraction time 60 min, CO2 flow rate 30 Kg/h, separation kettle I temperature 45 ℃, separation II pressure 8 MPa, temperature 40 ℃, separation III pressure 6 MPa, temperature 40 ℃.

As the pressure of the separation tank I increases, the amount of extract obtained from the separation tank I decreases.

The reason is that when the pressure in the separation tank I increases, CO2 has a higher dissolving capacity in the separation tank I, so that the volatile components desorbed from the separation tank I are reduced, and more volatile components are brought to the separation tank II. , Ⅲ was resolved.

The results showed that the color and quality of the volatile components of Pandanus sylvestris were improved when the pressure of the separation tank I was 12 MPa. When the pressure of the separation tank Ⅰ was 15 MPa, the color, quality and overall quality of the volatile components of Pandanus spp. The yield is better than when the separation pressure is 12 or 18 MPa;

When the pressure of separation tank I was 12 MPa and 15 MPa, the yield of squalene was higher; although the change of pressure in the separation tank I had no significant effect on the yield of squalene, it significantly affected the quality of volatile components.

In a comprehensive evaluation, the pressure of the separation vessel I was initially selected as 15MPa, and other parameters of supercritical CO2 extraction were further tested and investigated.

Separation Ⅰ Influence of temperature

Accurately weigh 300 g of the processed Pandanus leaves and put them into a 5 L extraction kettle. The extraction pressure is 21 MPa, the extraction temperature is 45 ℃, the extraction time is 60 min, the CO2 flow rate is 30 Kg/h, and the separation kettle I pressure is 15 MPa. When the pressure of Ⅱ is 8 MPa, the temperature is 40 ℃, the pressure of separation Ⅲ is 6 MPa, and the temperature is 40 ℃.

The temperature of the separation tank I has less effect on the yield of the volatile components from the different separation tanks than the pressure of the separation tank I, but it also affects the quality of the sample.

When the temperature of separation kettle I is 45℃, the extraction effect of volatile components and squalene in Pandanus sylvestris reaches its maximum value, and the appearance of samples of volatile components from Pandas sylvestris is better, and the separation effect is better. When the temperature continues to rise , The volatile components of Pandanus odorifera and the yield of squalene are slightly reduced.

There are two main reasons for this result: On the one hand, when the pressure of the separation tank is constant, the increase of the separation temperature can reduce the density of the CO2 fluid, and the solubility of the volatile components in the CO2 will be correspondingly reduced, which is beneficial to the extraction of the substance. Separate.

On the other hand, after the separation temperature rises, the volatility of the extracted substances increases, especially the low-boiling fragrance components are volatile, which is not conducive to separation.

In addition, when the temperature of the separation vessel I is 45°C, it is also in line with economic principles.

The influence of separation Ⅱ pressure

Experimental conditions: accurately weigh 300 g of the processed Pandanus leaves and put it into a 5 L extraction kettle, the extraction pressure is 21 MPa, the extraction temperature is 45 ℃, the extraction time is 60 min, the CO2 flow rate is 30 Kg/h, and the pressure of the separation kettle I 15MPa, temperature 45 ℃, separation II temperature 40 ℃, separation III pressure 6 MPa, temperature 40 ℃.

When the pressure of separation II was 12 MPa, almost all the volatile components of Pandanus sylvestris came out of Ⅲ, and under this separation pressure, the color and quality of the volatile components of Pandanus sylvestris was significantly improved. Under this separation pressure, the yield of squalene is higher. Therefore, the pressure of Separation II is determined to be 12 MPa.

Test results

Fine-tune the optimized conditions obtained by the process:

When the extraction pressure was 20 MPa, the extraction temperature was 45°C, and the separation Ⅰ pressure was 12 MPa, the separation Ⅰ temperature was 45°C, the separation Ⅱ pressure was 12 MPa, and the temperature was 40°C; the separation Ⅲ pressure was 6 MPa, the temperature was 40°C, and the extraction time was 60 min. Verification experiment.

The R1 and R2 values ​​of the volatile component yield and squalene yield of the three batches of verification tests were slightly lower than the predicted value of the model. The results are in good agreement with the model, and the extraction method is reliable and stable.

Discuss

  • Water has a certain solubility in high-pressure CO2, which can promote the solubility of the target product to a certain extent. A certain amount of water in the material is beneficial to extraction [7], so this paper conducts a single factor investigation on the water content of medicinal materials.
  • The extraction pressure has a significant effect on the extraction effect of the volatile components of Pandanus sylvestris and squalene. Therefore, the selection of the optimal extraction pressure should be determined by comprehensive consideration of the evaluation results of the experiment.
  • The experimental results show that the extraction temperature is also an important factor in the supercritical CO2 extraction of Pandanus. Since the effect of temperature on solubility is also closely related to the extraction pressure [8], the appropriate extraction temperature should be selected under different pressure conditions as much as possible. In addition, when selecting the temperature, the sensitivity of the extracted Pandanus aroma components to temperature should also be considered.
  • This study investigated the effect of different separation pressures on the yield and quality of volatile components in Pandanus sylvestris under the same extraction conditions.
  • By adjusting the pressure of different separation tanks, the ratio and quality of the volatile components of Pandanus spp from different separation tanks can be changed.
  • In the preliminary experiment in this paper, when the pressure of separation tank I is 6MPa, the volatile components of Pandanus sylvestris basically all come out of the separation tank I, the oil sample is turbid, the quality is poor, and the color is dark green. Therefore, when the pressure level of the separation tank I is selected, The minimum separation pressure level is 9 MPa.