Views: 0 Author: Site Editor Publish Time: 2022-11-10 Origin: Site
Lutein, also known as phytolutein, is a natural plant pigment with anti-oxidation, retinal protection, enhancement of human immunity and other effects, as well as toning effect, widely used in medicine, health products, food, cosmetics and feed. Vegetables, fruits and carrots are rich in lutein, among which marigold has the highest lutein content.
Lutein has 3 chiral centers and has 8 stereoisomers.
Lutein has a faint hay-like odor.
Lutein is insoluble in water and propylene glycol, slightly soluble in oil and n-hexane, soluble in acetone, dichloromethane and ethanol, easily soluble in ethyl acetate, tetrahydrofuran, chloroform, etc. Its stability in solvent is absolute ethanol >ethyl acetate>tetrahydrofuran>toluene.
The stability of lutein is poor, and it is mainly affected by factors such as oxygen, light, heat, metal ions, pH, etc. For example, the heat treatment process can cause isomerization of lutein to produce 9-cis and 13-cis lutein. Therefore, when storing, the pure lutein crystal or the lutein-containing material should be sealed in a vacuum or filled with an inert gas to avoid light and stored at low temperature.
Lutein is safe, non-toxic and harmless, and with its special physiological effects, it is in line with the development direction of "natural", "nutritious" and "multi-functional" food additives, and can be combined with vitamins, lysine and other common food additives. The same can be added directly to food. Lutein is an important natural pigment and natural health product, and is a green healthy food raw material.
Mammals such as humans cannot synthesize lutein by themselves, and foreign food is the only source of lutein intake. The content of zeaxanthin and lutein in egg yolk is the highest, accounting for 85% of the total carotene, and the content of lutein in corn is also very high, accounting for 60% of the total carotene in corn.
Lutein has a wide range of food sources, and it often coexists with zeaxanthin in nature. It is the main component of plant pigments such as corn, vegetables, fruits, and flowers. Lutein is found in more orange-yellow fruits and vegetables such as papaya, pumpkin, citrus, wolfberry, peaches, etc., but the most abundant ingredients are in green leafy vegetables, such as kale, spinach, leeks, cabbage, celery leaves, Coriander etc.
Lutein is a kind of fat-soluble vitamin, and its absorption spectrum contains near blue-violet light, which can help the retina of the eye to resist ultraviolet rays. Lutein is an important antioxidant for the eyes. Supplementing a large amount of lutein to the human body helps to maintain the durability of vision, improve visual response time, and reduce visual damage. For young people with myopia, supplementing lutein can delay the increase of their myopia, and regular use of lutein can effectively prevent the damage of computer radiation to the human body.
Lutein is widely used in condiments, tobacco, cakes, confectionery and various feed processing. In China, lutein has been widely used as a colorant.
Oxygen free radicals in the human body are an important cause of many age-related diseases. Lutein has strong antioxidant capacity, which can inhibit the activity of oxygen free radicals and prevent the damage of oxygen free radicals to normal cells.
The latest research findings found that lutein can slow the development of early arteriosclerosis. After animal experiments, it was found that the incidence of arterial thrombosis was lower than that of mice without lutein-containing diets when lutein was mixed with mouse feed and fed to them.
Lutein can be used as an effective adjuvant to enhance the hypoglycemic function of insulin. Therefore, eating foods such as fruits and vegetables rich in lutein can reduce the risk of diabetes.
According to the various functions of lutein, the following categories of suitable groups can be listed. When eating lutein, you should also pay attention to the appropriate amount, and eat it with other nutrients.
1. Adolescents: Adolescents are in a period of growth and development, and they should also pay attention to vision maintenance during the process of reading.
2. Specific staff: need to work in the noon sun (athletes, pilots, guards, traffic police)
3. People suffering from ophthalmic diseases: people with cataract, glaucoma, presbyopia, amblyopia, strabismus, astigmatism, regular and quantitative consumption of lutein has a relieving effect.
4. Office workers: Workers who often use computers or stare at TV screens and people who often stay up late or night workers.
5. Patients with other diseases: cardiovascular disease, kidney disease, proteinuria, diabetes.
There is a new type of tumble dryer that dries and thumps calendula and lutein. When the fluctuation rate of the pendulum is 70% to 90%, the content of lutein is determined by the drying time; when the drying time is the same, the amount of lutein obtained at 70 °C is less than that obtained at 60 °C.
The organic solvent extraction method is the most widely used method for extracting lutein. Lutein in marigold is highly soluble in ethanol, but insoluble in water under neutral conditions. The solubility of lutein under alkaline conditions is higher than that under acidic and neutral conditions.
Microwave is an instantaneous penetrating heating method, under the action of microwave field, the plant cell wall is broken, thereby accelerating the extraction rate and effectively improving the product yield. Microwave extraction technology has also achieved good results in the extraction of natural pigments. The advantage is that it not only reduces equipment investment and operating costs, but also meets environmental protection requirements.
The focus of supercritical CO2 extraction technology is a method of extracting active substances from animals and plants. This method is mainly based on the application of the properties of supercritical fluids. The pressure is adjusted to extract the desired substance. At present, the scale of supercritical CO2 extraction of many natural products has been expanded, from the experimental scale to the industrial production scale. The supercritical CO2 extraction method has many advantages, such as high purity, less solvent consumption, strong dissolving ability, non-toxic, harmless and so on. This method makes up for the defects of the organic solvent extraction method, and has high efficiency, short time consumption and simple operation.
The enzyme-assisted extraction method refers to the use of cellulase to process and break the cell walls of animals and plants, so that the substances in the cells are easily exposed during extraction, and the permeability of the oil is improved, which is beneficial to the subsequent extraction. It is caused by the enzymatic degradation of marigold, and the content of all-trans lutein reaches the highest level in the enzymatically treated marigold powder.
High performance liquid chromatography is a highly sensitive, efficient and rapid separation method, which can accurately detect the content of various components in its samples. It is the most widely used detection method for quantitative analysis of lutein. method. The method has high accuracy and good stability, and can efficiently and rapidly detect the content of lutein in the sample.
Colorimetry is based on the Lambert-Beer law. The most common one is UV-Vis spectrophotometry, which is a simple, fast, and low-cost detection method, which is used for accurate analysis according to the concentration of the measured substance in direct proportion to the absorbance. This method cannot analyze different isomers of lutein, has poor sensitivity, and is susceptible to interference. These are the outstanding shortcomings of UV-Vis spectrophotometry, which seriously restrict its application and development.