Tea polyphenols, GTP for short, are the general names of catechins, acetone, phenolic acids and anthocyanins in tea. Because its chemical structure contains many active hydroxyl groups, it is extremely beneficial to human health care and has many functions such as bacteriostasis, sterilization, anti-tumor and radiation resistance. As an additive for medicine and food, its development and application prospects are very promising.

First, the extraction process of tea polyphenols

Traditional methods for preparing tea polyphenols from tea mainly fall into the following three categories.

Soak tea leaves in polar solvent by solvent extraction, then separate the extract by liquid-liquid extraction, and finally concentrate to get the product. At present, this method is mainly used in industrial production. The product yield is 5%~ 10%, and the product purity is 80%~98%. The solvents used are acetone, ether, methanol, hexane and chloroform. This method has high production cost and is easy to cause pollution.

Ion precipitation method is to precipitate tea polyphenols with metals to separate them from caffeine. This method uses heavy metals toxic to human body as precipitant, so the products produced by this method are difficult to meet the requirements of food and pharmaceutical industries.

Column separation preparation methods include gel column method, adsorption column method and ion exchange column method. The key of this technology is column packing and leaching. The results show that the yield of tea polyphenols is between 4% and 8% and the purity can reach 98% by column separation preparation method, but the column packing is very expensive and needs a variety of organic solvents to elute, which is obviously not suitable for industrial production.

There are some problems and shortcomings in the above traditional methods, and the products can not meet the requirements of food additives and pharmaceutical industry in terms of safety, price and purity. In order to solve these problems, recently, through repeated experiments by relevant experts, a new process of preparing high-purity tea polyphenols by combining supercritical CO2 extraction technology with traditional extraction, concentration and extraction technology was successfully developed. This process not only improves the purity and yield of tea polyphenols. It also meets the requirements of industrial production on raw materials, solvent use, production route, production process safety, product color, yield and purity, and is beneficial to the more effective application of tea polyphenols in medicine and food industry.

Second, the application of tea polyphenols

The main uses of tea polyphenols are as follows:

Antioxidant effect of oil Tea polyphenols are antioxidants of natural oils. Its antioxidant activity is better than that of synthetic antioxidants such as butylated hydroxyanisole (BHA) and dibutyl hydroxytoluene (BHT), and it is also better than VE. It can be widely used in food industry to prevent and delay the oxidation or rancidity of oil.

Pigment protection tea polyphenols can prevent natural pigments and β -carotene from degrading and fading, which is said to be 20 times higher than VC.

Deodorant Because tea polyphenols have a good deodorizing effect on methyl mercaptan, Japan used it to make deodorized chewing gum and cigarette filters, which can remove and prevent smokers' bad breath.

Antioxidant and anti-aging tea polyphenols can eliminate excessive free radicals in human body and slow down human aging. A large number of experiments show that the antioxidant activity of tea polyphenols is stronger than VE, and the effect is better if it is combined with VC and VE.

Anti-caries tea polyphenols can strongly inhibit cariogenic bacteria, significantly reduce plaque and periodontal index, but have no effect on other beneficial microorganisms in the oral cavity.

The antibacterial effect of antibacterial and antiviral tea polyphenols is that polyphenols can precipitate bacterial proteins and denature and inactivate them. Based on the antibacterial and antiviral principle of tea polyphenols, catechins have been used in air conditioners abroad. Since 1998 went on the market, this new air conditioner has been well received by the market.

Tea polyphenols have the effects of reducing blood lipid and inhibiting atherosclerosis, and play an important role in body fat metabolism, which can obviously inhibit the increase of cholesterol content in plasma and liver and promote the excretion of lipid compounds from feces, so it can not only prevent atherosclerosis, but also lose weight.

Tea polyphenols, especially catechin derivatives, have many pharmacological effects, such as inhibiting the proliferation of cancer cells, anticancer and antimutagenesis. In addition, catechin derivatives can also reduce the toxic effect of heavy metals on human body and have anti-radiation effect. An American company has used this function to develop foundation cream cosmetics. The product label function is to prevent skin cancer caused by ultraviolet radiation and prevent early skin aging.

In other aspects, the application of tea polyphenols in fish oil products can effectively prevent the peroxide decomposition of polyene esters and acids, and its antioxidant capacity is stronger than VE. Tea polyphenols oil-soluble emulsion used in food blending oil can effectively prolong the induction period of rehabilitation, showing stronger antioxidant capacity than powder.

Tea polyphenols have become a new medicine and food additive. At present, in addition to tea polyphenols tablets and capsules, they are also widely used as antioxidants and food additives, and are used in cereals, oils, convenience foods, aquatic products, meat products, condiments, sweets, beverages and other foods. Products are in short supply, and the development and application prospects are very broad.