Green tea extract has a broad application prospect

Green tea extract Its main components include tea polyphenols, caffeine, aromatic oil, water, minerals, pigments, carbohydrates, proteins, amino acids and various vitamins It has the functions of lowering blood pressure, anti hemagglutination, lowering blood lipids, lowering blood sugar, reducing weight, preventing atherosclerosis, preventing skin allergy, removing skin pigments, preventing caries, plaque, periodontitis and halitosis Especially tea polyphenols, as natural antioxidants, have strong antibacterial and enzyme inhibiting effects, and have broad application prospects in food, medicine, health care and many other aspects In the future, the market of green tea extract will take tea as the raw material to extract tea polyphenols, which has the most Chinese characteristics and advantages It is also the inevitable way out for the crude old tea, a by-product of tea production The development of turning waste into treasure will make the health care function of tea better benefit human beings and have considerable economic benefits As a natural antioxidant for food, the price of tea polyphenols is generally 1-1.5 million yuan / ton; as a raw material of health products, the price can reach 1.6-2 million yuan / ton In the next five years when synthetic food antioxidants and natural products coexist, the annual demand for tea polyphenols will gradually change from 500 tons to 5000 tons, and will rise to tens of thousands of tons in the future As the main material of health products with huge added value, tea polyphenols will gradually increase from dozens of tons to hundreds of tons The extraction technology of green tea extract tea polyphenols is the general term of catechins, flavonoids, phenolic acids and anthocyanins in tea, accounting for about 15% - 25% of the dry weight of tea The most important component of tea polyphenols is various catechins of flavanols The research and development of tea polyphenols in the 80s of last century, entered the climax after the 90s of last century At present, the research on Purification and application of tea polyphenols has been concerned at home and abroad, and is still in the ascendant stage The research on the preparation of tea polyphenols from tea is mainly found in some patents and literatures, which can be divided into three categories according to different separation methods: solvent extraction, ion precipitation and column separation The solvent extraction method is to use polar solvent to extract tea, and then to separate the extracted liquid by liquid-liquid extraction, and finally to concentrate and get the product At present, the industrial production of tea polyphenols mainly uses this method The yield of the product is 5% - 10%, the purity of the product is about 80% - 98%, and the caffeine is 4% - 7% The organic solvents used are acetone, ether, methanol, hexane and chloroform However, the method uses a variety of organic solvents, and the production cost is high Some toxic organic solvents make the product and operation unsafe, and easy to cause environmental pollution The ion precipitation method uses metals to precipitate tea polyphenols and separate them from caffeine, such as copper salt, lead salt or aluminum trichloride Because the method uses heavy metals which are toxic to human body as precipitant, its products are not accepted by food and medicine industry The gel column, adsorption column and ion exchange column have been reported for column separation In recent years, more attention has been paid to the study of improving the purity Therefore, there are more studies on chromatographic column separation The key of this technology is column filler and leaching The results showed that the yield of tea polyphenols prepared by column separation was between 4% and 8%, and the purity of tea polyphenols was 98.1% If the gel column was separated, it could be highly decaffeinated, and its residue was only 0.1% However, column filling materials such as adsorption resins and lipophilic gels are very expensive, and a large number of organic solvents are used when washing Obviously, it is not suitable for industrial production of tea polyphenols At present, there are about thirty or forty tea polyphenol plants that have been built or are under construction in China, but only three or four of them are truly competitive in the market (product quality, scale, cost and efficiency) The main reason is that the existing factories all adopt the traditional solvent extraction method and precipitation separation, without the use of high-tech means, the product color, purity, solvent residue and caffeine content can not meet the increasing requirements of domestic and foreign merchants Especially due to the use of a large number of flammable and explosive organic solvents in the process, some even use toxic chloroform and other solvents, resulting in poor safety, poor quality and high comprehensive cost In the food additive industry, the price cannot compete with some synthetic antioxidants, and in the health care industry, the purity cannot meet the requirements These problems can not be solved by the existing traditional technology Using supercritical carbon dioxide extraction technology, combined with traditional technology to produce high-purity tea polyphenols, can not only produce high-quality tea polyphenols, but also solve some disadvantages of traditional technology By combining supercritical carbon dioxide extraction technology with traditional extraction, concentration and extraction technology, a new process for the preparation of high-purity tea polyphenols was obtained Its advantages are as follows: 1 The amount of organic solvent is reduced, the safety is good, and the pollution is less; 2 The yield is high; 3 The residual solvent can be completely removed; 4 The comprehensive cost is low The process not only improves the purity and yield of tea polyphenol, making its content more than 90%, caffeine content less than 2%, and solvent residue zero, but also meets the requirements of industrial production for raw materials, used solvents, production route, production process safety, product color, yield, purity and other aspects, so as to be more effective in the food and pharmaceutical industry It is also reported that the absorption rate of tea polyphenol and caffeine can reach 8.6% and 1.6% of the dry tea weight respectively by the combined production process of extracting tea polyphenol and caffeine by resin adsorption, using green tea, broken old tea pieces, tea clothes, tea powder and other raw materials.