4 CO2 extraction process parameters
The average yield of tomato powder is (2.59±0.1)%.
Wash and weigh the fresh tomatoes, put them in the crusher, add 2 times the volume of water, stir evenly, and put the homogenate in the centrifuge. Centrifuge at 4000 r/min for 10 min, take out the precipitate, weigh it, and put it in the refrigerator.
After pre-frozen, freeze-dried in a freeze dryer for 2 days, grind into tomato powder, weigh the mass of tomato powder and calculate its yield, and store it in a brown bottle protected from light.
When the extraction pressure was 35 MPa, the extraction rate reached the maximum value of 73.8%.
The extraction rate of lycopene first increased and then decreased with the extraction pressure. This is because when the extraction temperature is fixed, the density of supercritical CO2 increases with the increase of the extraction pressure, which causes the solubility of the solvent to increase, and the extraction pressure is too high, which in turn causes interactions between various molecules, and finally condenses the modifier This leads to a decrease in solubility and changes the extraction rate.
When the extraction temperature is raised from 35 ℃ to 45 ℃, the extraction rate of lycopene is significantly improved, which shows that the influence of extraction temperature on the solubility of supercritical CO2 is less than that on the volatility of the extract.
When the extraction temperature reaches 45 ℃, the extraction rate is 80.8%; when the extraction temperature is increased from 45 ℃ to 55 ℃, the extraction rate of lycopene is significantly reduced. At this time, the influence of the extraction temperature on the solubility of the extract is greater than the influence of the extraction temperature on the volatility of the extract. At the same time, because lycopene is a heat-sensitive material when the extraction temperature is higher than 50 ℃ for a long time, it will partially degrade lycopene, which is also the reason for the decrease in extraction rate.
In experiments in other universities, hot-air dried tomato powder was used as raw material, and the optimal extraction temperature obtained by supercritical CO2 was 50 ℃. This may be related to factors such as raw material pretreatment methods, test equipment, and tomato varieties, which led to the experiment. There is a deviation.
When the static extraction time is 90 min, the extraction rate of lycopene reaches the maximum value, which is 90.7%.
Under the static extraction time of 30~90 min, the extraction rate of lycopene increases with the increase of the static extraction time. This may be because within 90 minutes, the longer the extraction time, the longer the interaction time between the supercritical fluid and the extracted material, so the extraction rate increases accordingly. After reaching the peak, as the static extraction time increases, the lycopene The extraction rate of lycopene is reduced, which may be because the heat-sensitive lycopene is heated at 45 ℃ for a long time, which causes part of the lycopene to degrade and volatilize, which reduces the extraction rate.
Summary of the CO2 extraction process
Supercritical co2 fluid extraction is a separation technology that extracts target components by heating and pressurizing the fluid at a state higher than the critical extraction temperature and critical pressure. The density of the supercritical fluid can be changed by changing the extraction temperature or pressure, thereby changing the fluid’s density. Solubility.
In our experiments, we select the main factors that have a significant influence on extraction pressure, extraction temperature, time, and CO2 flow rate, and use the single factor and response surface method to determine the best process for supercritical CO2 extraction of lycopene: pressure is 35 MPa, CO2 flow rate It is * L/h, the extraction temperature is 46 ℃, and the extraction time is 90 min.
Under these conditions, the optimal extraction rate of lycopene was 90.21%, and the measured lycopene content was 3648.57 μg/g. Compared with raw materials that have not been processed and dried, the extraction rate under the optimal process conditions is improved.
The best CO2 extraction process of lycopene
The optimal extraction rate of lycopene was 90.21%, and the measured lycopene content was 3648.57 μg/g.
- Extraction pressure: 350 bar;
- Extraction Temperature: 46 ℃;
- Separation pressure: 110 bar;
- Separation temperature: 55℃;
- Extraction time: 90 min.
In comprehensive considerations, the static extraction time of 90 min is more appropriate.
4 methods of lycopene extraction
Lycopene is a berry pigment body synthesized by red pigment and stored in tomatoes. It is one of the carotenoids and the carotenoid with the highest degree of unsaturation.
It is widely used in foods and medicines, and as a natural dye in cosmetics. It has anti-oxidation, anti-cancer, and anti-aging functions. Many in vivo and in vitro studies have proved that lycopene can pass its strong antioxidant activity and incomplete Learn about other functions to prevent cardiovascular disease, cancer, and diabetes.
The extraction process of lycopene mainly includes the organic solvent extraction method, supercritical CO2 extraction method, HPLC method, enzymatic method, microbial fermentation method, and direct crushing method.
Enzymatic extraction takes a long time, and the temperature must be strictly controlled during enzymatic extraction. In addition, when the enzyme is in an organic solvent, the enzyme activity is affected to a certain extent, resulting in a certain difference in the extraction rate of lycopene.
The organic solvent method is used to extract lycopene. When the organic solvent method is used to extract lycopene, the solvent loss is large, the time-consuming is long, the yield and purity are low, the selectivity is not high, and the safety risk is high.
Saponification pretreatment and microwave
Saponification pretreatment and microwave technology are optimized for extraction. Although the yield of microwave-assisted extraction of lycopene is relatively high, microwave extraction is easy to destroy the material structure, and lycopene is prone to isomerization at higher extraction temperatures. Chemical reaction and oxidative degradation reaction.
CO2 extraction method
The supercritical CO2 extraction method has the advantages of high selectivity, short extraction time, non-toxic extraction solvent, and high extraction rate.