Green Tea Polyphenols (GTPs) are light green or light yellow powders containing four compounds: catechins, flavones, phenolic acids and anthocyanins. Catechins contain three free states: catechin (C), epicatechin (EC) and epigallocatechin (EGC) and two gallates: epicatechin gallate (ECG) and epigallocatechin gallate (EGCG). EGCG is the most important and most bioactive.
According to Chinese manufacturers, it is possible to extract 1t of GTPs from 15-20t of fresh green tea. Traditionally, there are three processing methods for GTPs: organic solvent extraction; ion precipitation and then extraction; and column absorption, separation and extraction. Organic solvent extraction is the most widely used. By using solvents like acetone or chloroform in the first extraction and ethyl acetate in the second extraction, the manufacturers can separate catechines from theine and other compounds. Then they get GTPs with a high catechine content (80-98%) by concentration, column separation and spray drying. Currently China has 30-40 GTP manufacturers with a combined capacity of almost 8,000t/year, with the top five accounting for about 75% of this.
Latest innovations in green tea polyphenol processing technology
Researchers have been experimenting at the laboratory scale with new column separation techniques that significantly increase yields and purity, although scaling them up to commercial production has proved difficult and expensive.
However, the leading manufacturers all claim to have improved their processes in recent years, notably market leader Taiyo, which operates China's largest GTPs facility, where it has installed new ceramic membrane filtration extraction technology, an online cleaning system, reverse osmosis and thin film concentration systems.
Honghe Tangren meanwhile, has developed new patented extraction technology, and installed a series of units for tea marinating, filtration, removing pectin by ultrafiltration, concentration by nano-filtration or reverse osmosis, vacuum concentration and spray drying, which it claims has helped it achieve purity of 98% and far higher yields.
Some manufacturers have also experimented with extraction using CO2 Supercritical Extraction equipment.
Finally, Chengdu Biopurify, a herbal extract manufacturer in Chengdu, Sichuan, is refining high-purity EGCG (98-99%) from the common GTP raw material by using dynamic axial compression column chromatography for the purpose of separation. According to Biopurify, extraction is done using an innoxious solvent, and drying without frozen-drying equipment, dramatically reducing production costs.
- Prices**
The percentage of EGCG in the product has become the indicator of GTP prices. Taiyo claims its products contain 90% EGCG, while DSM claims its Teavigo product has more than 95%. In China, suppliers currently quote RMB700-800/kg on 95% product. For 80% and 60% concentration, the prices are around RMB400 and
Applications
Antioxidants
In 1990, researchers from Zhejiang University Tea College released a report indicating that catechins contain more than two active phenolic hydroxyl groups (-OH), which can disable harmful free radicals and protect lipids from oxidation. An application to China's National Food Additive Standardization & Technology Committee and Ministry of Health to use GTPs as antioxidants in foods rapidly followed, and was approved. In China, GTPs are now classified into the antioxidant category of food additives and are increasingly used in meat, fish and edible oil applications to protect polyunsaturated fatty acids (PUFAs) from oxidation.
Controlling blood pressure, blood glucose and blood fat
Since the 1990s, several Chinese studies into the effects of green tea on blood pressure, blood sugar and blood fat have been conducted, prompting a flurry of new launches in the dietary supplement market. In one human clinical study, volunteers taking 500mg green tea catechins a day for three months saw clear reductions in blood pressure. Japanese animal studies have also suggested that foods with 0.1-0.5% EGCG can decrease 'bad' LDL cholesterol and increase 'good' HDL cholesterol. A test conducted in China on 120 high blood-fat patients also demonstrated that EGCG can restrain the agglomeration of blood platelets (thin the blood).
Weight management
GTPs clearly have a promising future in the weight management market, with increasing demand from the US market. The US Food and Drug Administration has also regulated to inhibit the use of ephedrine, with many dieters now looking to GTPs as a substitute.
Beauty
Green tea extracts as beauty ingredients have also become hot in China. Lin Qing Xuan (Shenyang, Liaoning), a leading beauty product manufacturer and marketer, produces GTPs capsules as dietary supplements for beauty following a tie-up with Zhejiang University Tea College. The capsules combine several natural raw materials including GTPs, aloe, safflower, American ginseng, pearl and vitamin C, and have had some success in three regional market sectors: Jiangsu, Zhejiang and Liaoning, says the company.
Cancer risk reduction
Researchers in Zhejiang University Medical College have found that GTPs (especially EGCG) can restrain cancer cell proliferation and restore the sensitivity of drug-resistant cells against anti-cancer drugs. There also appears to be some potential for green tea in skin protection, with animal studies suggesting that EGCG can protect skin from the damaging effects of UV light. In China, concentrated green tea solutions are also used as white blood cell accelerators in radiation treatment.
Oral care
Clinical research suggests that GTPs can restrain cariogenic bacteria and reduce dental plaque, prompting a wave of applications in toothpaste and other personal care products. Japanese companies have also developed chewing gums containing green tea extracts that claim to tackle bad breath.
HIV
Several studies suggest that EGCG may also have a protective effect against HIV infection. One study led by Dr Kuzushige Kawai from the University of Tokyo has opened new doors for the clinical application of EGCG as a new anti-HIV drug. Further research is now being conducted at the National Center for Macromolecular Imaging at Baylor College of Medicine, Houston, Texas, and the Department of Molecular Biology and Biotechnology at the University of Sheffield, UK.
Top green tea polyphenol manufacturers in China
1 Wuxi Taiyo Green Power 2,500t/year
2 Honghe Tangren 1,500t/year
3 DSM Nutritional Products 1,000t/year
4 Changde Busun 650t/year
5 Zhejiang Painuo 500t/year
Wuxi Taiyo Green Power: - green tea market leader
Wuxi Taiyo Green Power is a Sino-Japan joint venture, co-founded by China National State Forest Farm Development Corporation and Japan Taiyo Kagaku in Wuxi City, Jiangsu Province in 2004. It originally purchased a patent from Procter & Gamble and started to produce GTPs in 1993. Its production capacity has increased to 2,500t/year, making it the leading GTPs supplier in the world.
DSM nutritional products: - Expansion plans for teavigo
DSM Nutritional Products in Shanghai Pudong plans to expand its capacity to 1,000t/year. Two new EGCG production lines are in the pipeline, so watch this space!