Pigment detection.
Summary of extraction and refining technology of capsicum pigment;
As an important part of colorants, natural plant pigments are widely used in food processing, medicine and cosmetics and other industries closely related to human health. Compared with synthetic pigments, natural plant pigments are rich in raw materials and have no toxic and side effects on human body, and most natural pigments have certain physiological functions, such as natural β -carotene has obvious effects on cancer prevention, anticancer and cardiovascular disease prevention. With the development of biotechnology, people pay more and more attention to the research and development of natural plant pigments, and its application has broad development prospects. Pepper pigment is one of the hot spots in natural pigment research. It is a mixed pigment containing many pigment components, including red pigment such as capsicum red pigment, capsicum red pigment and capsicum red pigment, and yellow pigment such as purple yellow pigment and yellow pigment.
At present, the main product of capsicum pigment is capsicum red pigment, which belongs to polyketene in carotenoids and is a mixture of capsicum red pigment, capsicum red pigment and β -carotene Safe and non-toxic, it can be digested and absorbed by human body, and can be converted into vitamin A in human body. The appearance of capsicum red pigment is dark red viscous oily liquid, which is easily soluble in vegetable oil, acetone, ether, chloroform and n-hexane, easily soluble in ethanol, slightly soluble in glycerol, and insoluble in water. It is stable to acid and alkali (more stable in acidic environment), difficult to destroy under heating conditions, strong in coloring and good in dispersibility, but poor in light resistance and oxidation resistance, with a wavelength of 265433. Chili red has bright color and high color value, and its color intensity is 10 times that of other pigments.
Based on the above characteristics of pepper pigment, scholars at home and abroad have done a lot of research on it and formed several mature extraction and separation methods. In this paper, the research results of extraction and refining technology of pepper pigment were briefly introduced, and the future research trend of pepper pigment was prospected.
Several typical extraction and refining methods of 1 capsicum pigment
1. 1 organic solvent extraction method
According to the physical and chemical properties of pepper pigment, the following methods are commonly used in industry: crushing the pericarp of mature and dried pepper fruit and extracting with ethanol, acetone, isopropanol or n-hexane. Considering that natural red pepper contains capsanthin, capsaicin, capsicum oil and other components, capsaicin, that is, capsaicin, is spicy and will produce irritating vapor at high temperature, so it must be removed in the refining process of capsicum pigment. In structure, capsaicin is a polar compound with amide bond and hydroxyl group in its molecule. Its crystal is monoclinic prism or rectangle, melting point is 665438 0℃, and it is soluble in dilute ethanol, ether, acetone, ethyl acetate and other solvents and alkaline aqueous solution. Considering the different solubility of capsanthin mixture and capsaicin in different solvents, we can use the solubility difference of capsanthin mixture and capsaicin to deodorize. Based on this principle, how [5] to separate capsanthin from capsanthin by n-hexane extraction, using the property that capsanthin is soluble in n-hexane. The operation steps are as follows: weighing the pedicled, seeded and crushed red pepper powder, using acetone as extractant, extracting under normal pressure, distilling and concentrating the extractive solution under reduced pressure at 90℃ and vacuum degree of 0.09MPa, and recovering acetone at the same time. The process of extracting capsanthin from acetone is essentially a mass transfer process between liquid and solid through interphase contact surface, and the mass transfer speed determines the size and operation time of mass transfer equipment. In order to improve the mass transfer rate, Soxhlet extractor was used to extract dried Chili powder. Weigh a certain amount of concentrated paprika crude product and extract it with a certain amount of n-hexane. See table 1 for the test results.
Color value is defined as absorbance per unit mass of raw material extract.
The method has the advantages of simple operation, high pigment recovery rate and high product yield, but the color value of the product is small. Because of the negative correlation between color value and spicy degree, it shows that this method is not thorough enough to remove spicy, and this method can be used in the case that capsanthin is the main product and the requirement for capsaicin content is not very strict. Zhang Zongen and others used acetone as solvent to extract capsicum oleoresin. The oleoresin has high yield, high color value, low capsaicin content and easy separation. Using acetone (50%) solution with pH greater than 10.37 for more than 5 times to remove the spicy taste, the red pigment without spicy taste can be obtained. The method is simple and feasible, and all the quality indexes of the obtained pigment meet FAO/ WHO standards.
1.2 column chromatography It is reported that capsaicin in pepper can still feel spicy even if it is diluted to 1: 100000, which greatly limits the application of pepper pigment. Therefore, in the process of extraction and separation of capsanthin, the removal of spicy components becomes a key step. The separation of capsicum pigment by silica gel column chromatography belongs to partition chromatography, which is based on the structural differences between pigment and capsaicin. The solubility in silica gel combined stationary phase and eluent is different, and the partition coefficient between stationary phase and eluent is different to achieve the separation effect. Yuan Qingyun studied the separation of capsanthin by silica gel column chromatography, and summarized the following technological process:
Pepper → selecting → pulverizing → adding enzyme → filtering → concentrating → extracting with ethanol and petroleum ether → filtering → concentrating → loading on silica gel column → eluting → concentrating → obtaining deep red viscous liquid.
The key points of operation are:
1) Enzyme addition: Enzymatic hydrolysis will free the pigment combined with protein, fat and sugar in cells, which is convenient for solvent extraction.
2) Extraction: the extract of 90% ethanol and petroleum ether (1: 1) is stirred at room temperature for overnight extraction, filtered and concentrated under reduced pressure. 3) The elution conditions were determined by TLC. When the volume ratio of petroleum ether to food grade 90% ethanol is 2 ∶ 1, the spreading effect is the best.
4) passing the extracted concentrated solution through a silica gel column with a diameter of 100cm and a height of 100cm, eluting with eluent, and collecting the red eluted part.
5) concentrating the collected eluted part under reduced pressure.
The red viscous liquid obtained in the experiment has a moisture content of 0.37%, a fat content of 90.68%, pigment: color scale E1%1cm (475 nm) =143, and contains no capsaicin. He, Suo Quanling, etc. [5] The method of extracting and refining paprika red pigment by column chromatography was also discussed: using acetone as extractant, crude paprika red was extracted from dry powder of paprika, then the crude paprika red was distilled and concentrated under reduced pressure, and refined by column chromatography. In view of the advantages of column chromatography, a large glass column was used for column chromatography separation, and silica gel with particle size of 74 ~ 152 micron was used as filler, and the mixed solution of petroleum ether and acetone (10: 1) was used as developing agent. Crude Chili powder is separated by column elution, and orange liquid (a small amount) flows out first, then capsanthin flows out, and finally a yellowish liquid with strong spicy taste that is difficult to elute. The red pigment product was collected, concentrated by vacuum distillation, and the color value was determined by 75 1 spectrophotometer. The color value was e1%1cm (460 nm) = 56.5. The average recovery rate of pigment was 67.2%.
In order to solve the problem that most of the existing literatures introduced the methods of extracting non-spicy mixed pigment from red pepper, but did not further separate and analyze the mixed pigment, a column chromatography method was proposed to separate yellow pigment from pepper pigment. In this method, silica gel is used as stationary phase, acetone and 95% ethanol are used as eluents of capsanthin and capsanthin respectively, and the amount of pigment separated each time is 4% ~ 2% of the mass of silica gel, and the separated liquid is distilled under reduced pressure to obtain concentrated products. Through this process, not only the yellow pigment, the main by-product of pepper pigment, can be obtained, but also the purity of the main components can be improved accordingly, and the red pigment with higher purity can be obtained.
Using column chromatography separation technology, adsorbent X and mixed eluent were used in pilot test to further separate red, orange and yellow from capsicum pigment, which can greatly improve the color value and hue of low-quality capsicum red pigment. Wu Mingguang et al. separated the free crystalline capsanthin monomer from pepper peel by column chromatography, and its content was over 95%, which was a breakthrough in the formulation of capsanthin in China.
1.3 supercritical CO2 fluid extraction technology
Because of the oiliness of capsanthin, there is a high solvent residue in the product of capsanthin extracted and separated by organic solvent. It is difficult to make the product meet the latest standards stipulated by FAO and WHO (FAO/ WHO, 1984) by using general eluent method, which greatly affects the practicability and export of capsanthin. Supercritical fluid extraction is a new chemical separation technology. The key of this technology is to understand the solubility of supercritical fluid and its changing law influenced by many factors. Supercritical CO2 fluid extraction (SCFE-CO2) is an extraction process with CO2 fluid whose temperature is higher than the critical pressure as the solvent. The fluid near the critical point not only has extremely high solubility to substances, but also the solubility of substances will change with the pressure or temperature of the system, so it is convenient to selectively extract and separate different substances by adjusting the pressure or temperature of the system. Supercritical separation technology has the advantages of simple process, low energy consumption, non-toxic extraction solvent and easy recovery. The purity of the obtained product is extremely high, and the residual solvent meets the requirements of FAO/ WHO. Zhao Yaping et al. used self-designed supercritical CO2 fluid extraction equipment to extract capsicum pigment. The equipment mainly consists of four parts: gas supply system, supercritical CO2 fluid generation system, extraction and separation system and metering system, and all components are made in China. Experiments show that the optimum extraction condition is particle size.
The capsanthin was separated and purified by supercritical extraction device produced by NOVA Company in Switzerland. The optimum technological parameters to make the product meet the FAO/ WHO residual solvent standard (hexane content ≤25mg/kg) are as follows: extraction pressure 65438±08 MPa, extraction temperature 25℃, extractant flow rate 2.0L/min and extraction time 3h. Under the optimum technological conditions, the color value of the product can reach 342. Han et al. used supercritical CO2 fluid extraction technology to refine capsanthin. The color value of capsanthin was 100 ~ 180, and the residual solvent was 30×10-6 ~150×10-6. The experimental results showed that the color of capsanthin was improved when the extraction pressure was controlled below 20MPa. It was found that using cosolvent, such as 1% ethanol or acetone, or increasing the extraction pressure could improve the yield of pepper pigment. The capsanthin isolated under low pressure is almost β-carotene, while a large proportion of red carotenoids such as capsanthin, capsanthin, zeaxanthin, β-cryptoxanthin and a small amount of β-carotene are obtained under high pressure. In the two-step extraction process, the technology of separating red pepper oil and β -carotene was adopted in the first stage, which ensured the enrichment of red pepper pigment in the second stage, and the ratio of red pepper to yellow pigment reached 1.8. The removal and refining technology of capsicum pigment was studied on a multifunctional supercritical CO2 fluid extraction fractionation device independently developed. The results show that yellow and spicy components can be extracted under the pressure of less than 65438±00.0 MPa, and the red pigment can be retained. When the pressure is greater than 12.0MPa, the red component can be completely extracted. Although supercritical fluid extraction of natural pigments has many advantages, it has not been widely used in this field in China because of the large one-time investment of supercritical equipment.
1.4 Other
The red pepper was separated by two-step extraction, that is, the red pigment, capsaicin and tar smell were extracted from dry-pointed pepper by organic solvent leaching, and then the tar smell was removed by supercritical CO2 extraction to obtain red pigment and capsaicin without organic solvent. The yield is 5-7 times higher than that of single supercritical extraction, and the quality is much higher than that of FAO/ WHO (1984). Yao and Jiang made 54 experiments with six separation and extraction methods. Through these experiments, we know that the yield and quality of capsanthin are closely related to the production technology and technological conditions. Through comparative analysis, we can compare the advanced nature and practicability of these six production technologies. The basic situation of the six processes is shown in Table 3.
As can be seen from Table 4, among the six production processes, the quality of capsanthin produced by process I is the best; The indexes of capsanthin produced by process ⅱ and process ⅲ meet the standard, but the color price is low. Obviously, processes Ⅳ, Ⅴ and Ⅴ can only extract crude products with low color value and low purity, which need further refining.
2 discussion
And prospect: At present, a variety of separation and purification processes of pepper pigment have been formed. Traditional production methods include organic solvent extraction, steam distillation and so on. However, these methods can not completely remove the spicy taste, capsaicin is difficult to recover and the yield of pigment is low. Moreover, the application of organic solvent extraction often makes the residual organic solvents such as acetone, dichloromethane, acetone and n-hexane in the product exceed the standard, which narrows the application scope of the product. Supercritical CO2 fluid extraction technology can greatly improve the quality of pepper pigment products, with high color value and low residual organic solvent. Without heat treatment, the original components in natural substances will not be destroyed, and SCFE-CO2 technology can be operated near room temperature, saving energy and removing the odor in pepper products. However, this method is complicated in operation and expensive in equipment. Silica gel column chromatography has the advantages of simple operation, low equipment requirements, good separation effect and thorough removal of spicy taste, which is suitable for small-scale development and production. According to the data, the process of separating capsanthin and capsaicin by double solvent extraction has a good extraction and refining effect. The latest research abroad shows that the extraction of carotenoids by subcritical propane is better than that by supercritical CO2 under mild conditions. Ultraviolet-visible spectrum analysis, thin layer chromatography, gas chromatography, high performance liquid chromatography and other analytical separation technologies have also been applied to guide the selection of production process parameters of capsanthin.
At present, there is still a big gap in the in-depth development of pepper pigment products in China, and the technical progress is slow. Extraction and separation of organic solvents are the main means. Due to the limitation of solvent method, it is difficult to improve the product quality and reduce the economic value of the product. Therefore, the deep processing research of pepper pigment products has high value and broad prospects. It is very important to avoid or reduce the loss of pigment components during initial processing and storage. In order to improve the light resistance, oxidation resistance and applicability of pepper pigment, it is hoped to transform fat-soluble pigment into water-soluble pigment and develop preparation technology and emulsification technology. The coordinated development of these pigment preparations and processing technologies meets the needs of development fields and market development. Single-component supercritical solvent extraction has some limitations, such as low solubility or selectivity of some substances in extractant, which leads to poor separation effect. The application of appropriate cosolvent (or entrainer) can strongly affect the solubility, selectivity and P-V-T properties of supercritical fluid. Therefore, in the process of supercritical fluid extraction of pepper pigment, developing suitable cosolvent can achieve more effective separation. Improving and introducing deodorization technology will be beneficial to the wider application of pepper pigment. Based on the research results of existing pepper pigment refining technology, it is of great significance to research and develop the extraction technology of pepper pigment with low investment, simple operation and high product quality.
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Chili red pigment
Capsaicin is a carotenoid and a popular antioxidant at present.
Pepper is an annual or perennial herb, belonging to the genus Capsicum of Solanaceae, which can bear spicy berries. Other aliases include pepper, sea pepper, Qin pepper, spicy eggplant, sweet pepper, vegetable pepper and pointed pepper. Every100g of fresh pepper contains 70-93g of water, 4.2g of starch, 0.2-2.0g of protein, and 73-342mg; Vitamin c; The dried pepper mainly contains vitamin A, and the spicy taste of pepper is capsaicin (C 16H27no3), which is mainly distributed in the diaphragm and epidermal cells around the placenta.
Pepper originated in tropical areas of Central and South America, and was introduced to Europe in 1493, and to Japan in 1583- 1598, but it was not introduced to China in specific time. The earliest record of pepper in China can be found in Eight Chapters of Respecting Life written by Gao Lian in Ming Dynasty (159 1). There are two paths for pepper to enter China. One is to declare the far-reaching Silk Road, which entered Gansu, Shaanxi and other places from West Asia, with a rate far from the northwest; First, it entered South China through the Straits of Malacca, and was cultivated in Yunnan, Guangxi and Guangdong in the south.
It is said that the earliest pepper grew in the jungle of Chile, domesticated and cultivated in Mexico, and then introduced to other countries in the world. Now, Chile has a traditional chili eating competition. However, botanists discovered wild-type millet pepper in the virgin forest of Xishuangbanna, Yunnan Province in 1970s, which attracted wide attention from families and plants. This may lead to disputes between exotic peppers and local peppers. If we discuss from the theory of continental plate drift, the east coast and west coast of the Pacific Ocean are originally a whole, but South China is also close to Central America.
Medicinal function of pepper
1. Pepper can burn fat.
Pepper contains capsaicin, which can accelerate the metabolism of fat and promote energy consumption, thus preventing fat from accumulating in the body. For people who are not good at eating spicy food, don't be too anxious to lose weight with Chili, eat regularly and let the gastrointestinal stimulation adapt slowly.
Recently, Japan has a new explanation for pepper. In Japan, people think that pepper is a "tonic" for women to some extent, rather than a "natural enemy".
Because they think that in addition to sterilization, it also contains a substance called "capsaicin", which can promote hormone secretion, thus accelerating metabolism to achieve the effect of burning body fat, thus playing a role in losing weight.
Moreover, the ingredients of pepper are natural and reliable. In addition, they also believe that in some areas where spicy food is the main food, local women not only have less acne problems, but also have smooth skin.
Second, peppers are good for your face.
Capsaicin in pepper can strengthen new blood circulation, expand facial skin and blood vessels, improve facial blood circulation and make face rosy. The premise is that enough is enough, beware of acne on your face.
Pepper can promote blood circulation. When capsaicin is applied to the skin, it will dilate capillaries, promote circulation and make the skin red and hot. At present, some manufacturers have used these principles to put capsaicin into socks and become "Chili socks" to keep warm in winter.
Pepper can relieve the discomfort caused by a cold. For thousands of years, spicy food has often been regarded as sweating and expectorant, and it seems so now. Spicy food can dilute secreted mucus, help expectorate, and not block the respiratory tract. Professor Evan Ziman of the University of California even said: "Many cold medicines and cough medicines sold in pharmacies have the same effect as Chili, but I think eating Chili is better because it has no side effects at all."
Third, pepper can relieve pain.
Capsaicin in pepper can reduce substance P in nerve cells and make the transmission of pain signals insensitive. Pepper can also be used to treat rheumatism.
Pepper has been used to relieve pain since ancient times, but scientists have only recently learned that capsaicin can deplete nerve conduction substances, which can transmit pain information to the nervous system. Through the analgesic principle of capsaicin, pepper paste has been used to relieve pain such as herpes zoster and trigeminal neuralgia.
In red and yellow peppers and sweet peppers, another component is capsanthin. Capsaicin is a carotenoid and a popular antioxidant at present. Raw peppers contain more vitamin C than oranges or lemons, and a bright red pepper provides almost half of the daily requirements recommended by nutrition experts. An ointment containing capsaicin is very effective in relieving the pain of herpes zoster.
Fourth, pepper can prevent cancer.
According to research, carotenoids in pepper not only contribute to vision, but also have the effect of anti-cell mutation.
According to epidemiological research, many ethnic groups who love spicy food, such as Southeast Asia, India and other countries, have a lower risk of cancer than western countries. Scientists speculate that these spicy foods contain a variety of antioxidants, and oxidation is directly related to chronic diseases, cancer and aging.
Recently, the University of Hawaii pointed out that carotenoids in peppers, carrots and other vegetables can stimulate genes that transmit information between cells (because the system of exchanging information between cells will fail when organs become cancerous), which may play an important role in preventing cancer.
Preventing arteriosclerosis A red pepper contains 1 day of β-carotene, which is a strong antioxidant and can inhibit the oxidation of low-density cholesterol (LDL) into harmful forms. Once LDL is oxidized, it will become a bad substance and block arteries, just like cream in the refrigerator. In other words, β -carotene began to intervene in the initial stage of arteriosclerosis.
Who should not eat more peppers?
Nowadays, dishes containing peppers are more and more popular with families. But from the point of view of health care, not everyone is suitable for eating Chili.
People suffering from fever, ulcer, chronic gastrointestinal diseases, hemorrhoids, dermatitis, tuberculosis, chronic bronchitis, hypertension and other diseases should not eat a lot of peppers.
Thin people should not eat more peppers. From the perspective of traditional Chinese medicine, thin people mostly belong to yin deficiency and heat constitution. The so-called "thin people have more fires" is open-minded. Such people often show dry throat, bitter taste, bloodshot eyes, top-heavy, irritability. If you eat more peppers, it will not only aggravate the above symptoms, but also easily lead to bleeding, allergies and inflammation, and even sores and carbuncles in severe cases.
Hyperthyroidism patients should not eat Chili. Patients with hyperthyroidism are often in a state of high excitement, and it is not appropriate to eat foods with strong irritation such as peppers.
Patients with nephritis should not eat Chili. Studies have proved that in the process of human metabolism, its irritating components are often excreted through the kidney, which has different degrees of stimulating effect on renal parenchymal cells.
The following is the identification of capsicum red pigment/khdt/khdt/200702/11153.html.