Carotenoid pigments are also called polyene pigments and polyterpene pigments. They are composed of 4 to 8 isoprene molecules and generally have conjugated double bonds.
Carotenoid pigments are widely found in nature, and there are many kinds of them.
At present, there are more than 1,000 carotenoid pigments with known structures. Carotenoid pigments have a wide range of uses, not only can be used as additives and colorants in food, medicine, cosmetics and feed, but also can improve immunity and antioxidant effects.
According to the chemical structure and solubility, this type of pigment can be divided into carrots and lutein.
Supercritical extraction technology has made great achievements in the extraction of natural pigments in China, mainly focusing on several types of pigments such as tetrapyrroles, carotenoids, and polyphenols. Among them, carotenoid pigments account for a large proportion.
Carrots are also called polyolefins and polyterpene olefins. They are conjugated olefins and are easily soluble in petroleum ether, such as lycopene and β2-carotene. Carotenoids are mainly found in green, yellow, red and other colored vegetables and fruits, such as spinach, cabbage, carrots, tomatoes, pumpkins, cantaloupes, etc.
Effect of pretreatment
Huidi et al. used tomato skin residue as raw material to extract lycopene with supercritical CO2 fluid, and found that tetrahydrofuran was used as pretreatment before extraction, and the extraction effect was better.
However, Zhang Jin et al. studied the effects of various process parameters on supercritical extraction of lycopene, and found that in addition to the main influencing factors such as extraction pressure, temperature, time and entrainer, pretreatment is also a key step that affects the extraction rate and purity.
The tomato skin is pretreated with saponification and ethanol, then supercritical CO2 is used as the fluid, 90% ethanol is used as the entrainer, and the extraction pressure is 35 MPa, the extraction temperature is 60 ℃, and the analysis temperature is 45 ℃. From 5 to 2.0 h, the extraction rate of lycopene can reach 93. 81%.
Influence of cosolvent
Zuo Airen et al. used vacuum-dried tomatoes as raw materials, extraction pressure 30 MPa, temperature 55 ℃, time 2 h, CO2 flow rate 30 kg/h, 30 ml soybean salad oil as cosolvent, and the extraction rate could reach 93.58%.
Giuseppe et al. use vacuum-dried tomatoes with a moisture content of 6% as raw materials, extraction pressure 45 MPa, temperature 66°C, CO2 flow rate 20 kg/h, particle size 1 mm, and 10% hazelnut oil as cosolvent, The yield of lycopene reaches 60%.
Using vegetable oil as a co-solvent not only improves the extraction rate, but also avoids the pollution of organic solvents to the product. There are no problems such as organic solvent residues, and the real green product is obtained.
Influence of extraction pressure
Li Jing and others applied supercritical fluid CO2 extraction technology to extract lycopene from autumn olive pulp, including optimization of extraction pressure, temperature, and cosolvent types.
The results show that increasing the pressure and using co-solvents can improve the extraction efficiency. At the same time, the content of lycopene in the product obtained by supercritical CO2 extraction technology is higher than that in the solvent method product.
Supercritical fluid extraction technology may become a technological choice for preparing lycopene from autumn olive fruits.
At present, the annual demand for β2-carotene in the world is about 1000 t, and the demand is increasing at a rate of 7-9% every year.
As a food additive and nutritional supplement β, 2-carotene has been recognized by the United Nations Food and Agriculture Organization (FAO) and the World Health Organization (WHO) Joint Expert Committee on Food Additives as a Class A Excellent Nutritional Pigment.
β2-carotene has a very broad market in the health care and pharmaceutical industries.
Cai Xiaozhan et al. used supercritical CO2 fluid extraction technology to extract β2 carotene from carrots, and obtained the optimal combination of extraction pressure 25 MPa, extraction temperature 50 ℃, CO2 flow rate 13 kg/h, extraction time 3.5 h, and various factors. The order of influence is extraction pressure>extraction temperature>extraction time>CO2 flow rate.
Song Shuhui et al. extracted β2 carotene from vacuum freeze-dried carrots under the conditions of extraction pressure of 50 MPa, extraction temperature of 60 ℃, CO2 flow rate of 1.5 ml/min, extraction time of 4 h, and 12.5% acetone entrainer, and the extraction rate reached 40.2%
Wang Jucheng et al. used seabuckthorn pomace as raw material and found that the optimal extraction pressure was 25-30 MPa, extraction temperature 35-40 ℃, separation pressure 12 MPa, separation temperature 60 ℃, CO2 flow rate 10 L/h, and extraction time 4 h.
Extract β2 carotene from Dunaliella salina
Carotene is currently a better way for humans to obtain β2 carotene from natural animals and plants.
Sui Xiao et al. discussed the appropriate process conditions for supercritical CO2 extraction technology to extract β2 carotene from Dunaliella salina, and found that under the conditions of extraction pressure of 30 MPa, extraction temperature of 45 ℃, CO2 flow rate of 10 L/h, and extraction time of 6 h, β, 2 The extraction rate of carotene is 95. 09%.
Compared with the conventional solvent method, supercritical CO2 extraction technology has the advantages of high extraction efficiency, fast speed, simple process, no solvent residue, and pure product color and taste.
Studies have shown that supercritical CO2 extraction of β2 carotene from Dunaliella salina has the value of industrial development.
The study also found that supercritical CO2 extraction conditions have a significant impact on the composition of β2 carotene isomers in Dunaliella salina.
β2-carotene plays a key role in the genetic toxicity and anti-genetoxicity of carrots. The content of cis-β2-carotene in the supercritical CO2 extract is 82.0%, which is much higher than the solvent-extracted cis-β2-carotene. content.
In terms of the physiological activity of β2-carotene, supercritical CO2 extract is better than solvent-extracted β2-carotene.
Xanthophylls are oxygen-containing derivatives of conjugated polyolefins, which are easily soluble in ethanol, mainly zeaxanthin, which exists in corn, pepper, peach, citrus and other plants.
The main components of zeaxanthin are zeaxanthin and cryptoxanthin.
The organic solvent residue and clarity of corn yellow pigment extracted by traditional methods do not meet the standard, and the product yield is also low.
In addition to avoiding the problem of solvent residue, the supercritical CO2 fluid extraction has better comprehensive indicators such as appearance, solubility, clarity, color and so on than the products obtained by organic solvent extraction.
In addition, supercritical CO2 fluid extraction of the residue is conducive to protein recovery.
Extraction case a
Zheng Hongyan and others used methanol, ethanol, acetone, and n-hexane as entrainers when extracting corn yellow pigment, and found that methanol has the best effect, followed by anhydrous ethanol, and acetone and n-hexane are inferior; considering the edibility of the pigment, choose Anhydrous ethanol is used as an entrainer.
Extraction case b
Li Jing systematically studied the temperature, pressure, time, entrainer and other process conditions of supercritical CO2 fluid to extract corn yellow pigment from corn gluten meal, and determined the best combination of supercritical CO2 extraction of corn yellow pigment, that is, the extraction pressure 25 MPa, temperature 45 ℃, 20% absolute ethanol as entrainer, extraction time 2 h, supercritical CO2 extract yield is 2.2% higher than the conventional chemical solvent method.
Extraction case c
Li Dajing uses supercritical CO2 extraction technology to extract corn yellow pigment from corn gluten meal, a by-product of corn starch processing, and uses a two-stage separation method to study the process conditions for supercritical CO2 extraction and separation of corn yellow pigment.
The results show that the process conditions for supercritical CO2 extraction of corn yellow pigment are: CO2 flow rate of 40 kg/h, temperature of 40 ℃, pressure of 35 MPa, and time of 90 min; the optimal separation conditions for obtaining high-quality pigment products are separation vessel I and pressure of 9 MPa , The temperature of separation vessel I is 45 ℃, and the temperature of separation vessel II is 50 ℃.
Capsicum red pigment is a natural red pigment extracted from the peel of mature pepper.
It has bright color, good thermal stability, is safe and harmless to human body, has dual functions of nutrition and coloring, and is an ideal colorant with broad development prospects.
At present, capsicum red pigment has been produced by supercritical CO2 extraction.
A lot of research work on the extraction of capsanthin by supercritical CO2 fluid has been done at home and abroad, mainly including the direct extraction and refining of capsanthin.
Zhu Kai et al. used the SCFE method to extract capsanthin from peppers, first extracted with organic solvents to obtain the crude capsicum extract, and then purified and refined. The best process conditions were the extraction temperature of 35 ℃, the extraction pressure of 17 MPa, and the extraction time of 4 h. In addition, a certain amount of alcohol-alkali-type entrainer is added, and the mass ratio of the crude capsicum extract and the entrainer is 1:10, which increases the color value of the extract from the original 60 to 150, and the product yield is 93%.
In addition, the capsaicin in pepper is a very useful raw material for medicine.
However, it has similar properties to capsicum red pigment, and the two are often mixed together, making it difficult to separate.
The supercritical technology can solve this problem, and there have been research results of extracting the pigment after removing the spicy.
Capsicum Extract Case One
Zhou Wenwen and others used capsicum as raw material to prepare capsaicin and capsaicin by supercritical fluid extraction, and studied the pulverization degree, extraction pressure, extraction temperature, separation pressure, separation temperature, fluid flow, and color value of capsicum red pigment. The relationship between the rate and the content and yield of capsaicin, the process method of supercritical fluid extraction of capsaicin and capsaicin is obtained.
The suitable operating conditions are: the crushing degree of raw pepper is 40-80 mesh, the extraction pressure is 20 MPa, the extraction temperature is 40 ℃, the separation pressure is 10 MPa, the separation temperature is 50 ℃, the CO2 fluid flow rate is 20 L/h, and the extraction time is 3 hours.
Under this process, the color value of capsanthin obtained in the experiment was 227.15, the yield of capsanthin was 9.54%, the content of capsaicin was 14.75%, and the yield of capsaicin was 3.19%. The order of the influence of various factors on the color value and yield of capsicum red pigment and the content and yield of capsaicin is extraction pressure> extraction temperature> separation pressure> CO2 fluid flow rate.
Capsicum Extract Case 2
Zhang Guoqiang extracts peel powder (chili powder) and pepper seed powder separately.
First, under the pressure of 14 MPa, the extraction temperature is 55 ℃, the entrainment extraction operation with the peel and water is used, and the circulating CO2 flow rate runs stably for 1.5 hours.
The process conditions have strong selectivity for capsaicin extraction. Compared with pure CO2 as the extractant, the extraction volume is increased by 8.7 times. Using ethanol as the entrainer, running at 28 MPa, it was found that the extraction effect of the spicy red pigment on the peel of the despicrin was strong, the spicy red pigment was bright in color, strong thermal stability, good emulsification and decomposition, and all quality indicators exceeded GB10783289, the color price of the product is 80-140, it is a natural edible red pigment.
Other lutein pigments
On the basis of preparing the mother liquor of double enzymatic hydrolysis of gardenia yellow pigment, Li Xionghui and others combined ultrasonic extraction and supercritical extraction to extract gardenia yellow pigment and achieved good results.
In 2000, Naranjo et al. studied the solubility of lutein diester in marigold in supercritical CO2 and the effect of carrier agents.
The Shanxi Institute of Coal Research of the Chinese Academy of Sciences has studied the supercritical CO2 production process of lutein in fermented dried fresh flowers. The extraction pressure is 20-40 MPa, the extraction temperature is 30-60 ℃, the supercritical extraction is 1-10 h, and the extract is separated under reduced pressure. The purity of the product obtained after saponification is 18%-22%, and the color value is 212-321.