Tea polyphenols is the general polyphenol compounds extracted from green tea . It is an amorphous brown powder, easily soluble in water, soluble in ethanol, methanol, acetone, ethyl acetate, and insoluble in chloroform.
The main components of tea polyphenols are catechins and their derivatives, which are the main chemical components with health care functions in tea. It has various physiological activities such as anti-oxidation, anti-radiation, anti-aging, lowering blood lipids, lowering blood sugar, inhibiting bacteria and inhibiting enzymes.
The color of tea polyphenols varies from light yellow to brown to white, with a slight tea fragrance and astringency; good heat resistance, hygroscopicity, stable at pH 2 to 7, and conditions are prone to oxidized in occurance of light or pH > 8.
1. Natural antioxidant
Tea polyphenol is an excellent natural antioxidant, and its antioxidant properties are closely related to the synergistic effect of each component. The best combination is EGCG (epigallocatechin gallate): ECG (epicatechin gallate):EGC(Epigallocatechin):EC(Epicatechin)=5:2:2:1. Moreover, tea polyphenols coordinate with other antioxidants , such as VC, VE, carotenoids and glutathione to enhance the antioxidant performance.
Acid heat stability of tea polyphenols:
Tea polyphenols are relatively stable to heat and acid. The 2% solution is heated to 120°C and kept for 30min without significant change.
At 160°C: 30min in oil and fat degrades 20%, and the 2% solution is kept at 37°C for 3 days.
Stable in the range of 2 to 7, 2% tea polyphenols in 2%, 5% and 10% salt solutions at pH=6.5 at room temperature for 3 days, the content assay remains the same. Treated with 12000Lx intensity of light for 1 month, the photolysis rate is 0, and the activity can also be maintained at 100% when treated at 100 ℃ for 1 h.
3. Moisturizing characteristics of tea polyphenols
Slightly hygroscopic, its water solution is 3 to 4 , prones to turn brown and get oxidized under alkaline conditions.
1.) Sensory indicators
powder, no foreign impurities visible to the naked eye
easily soluble in water
2.)Tea polyphenols by specification
Total number of bacteria
Total mold and yeast count
How to extract
Dissolve crushed green tea in hot water, aborsb tea fluid extract through polymer adsorbent, and then eluted with a 95% ethanol solution, gather Green tea polyphenols in ethanol, and collect ethanol by distillation, then concentrated under reduced pressure and spray-dried to obtain tea Polyphenols.