Yunnan Pu'er Tea is a unique Chinese tea that sells well in domestic and foreign markets. Pu'er Tea has many health functions such as blood fat reduction, weight loss, anti-arteriosclerosis, anti-cancer, anti-cancer, stomach protection and nourishing, and anti-aging. Yunnan Pu'er Tea is a fermented tea made from Yunnan large-leaf seed sun-green hair tea which is slowly and naturally fermented and artificially promotes solid-state fermentation. During the post-fermentation process with the participation of microorganisms, a series of significant changes in the chemical substances in tea have occurred, thereby forming the Puer tea's unique quality flavor and unique health-care functions, and its blood lipid-lowering effect is particularly significant.
The main chemical constituents of blood lipid reduction in Pu'er tea are tea polyphenols, tea polysaccharides, tea pigments, lovastatin and other substances.
In this paper, after the optimal extraction conditions of tea polyphenols, tea polysaccharides, and lovastatin were determined experimentally, different detection methods were used to detect and evaluate the lipid-lowering components in Pu'er tea, and the reasons for the differences were preliminary discussed. The optimized extraction conditions for catechin and gallic acid in Pu'er tea are: 75% ethanol solution sox reflux method is used to extract 90min and 120min, respectively. Based on the literature, this paper uses reversed phase high performance liquid chromatography, using C18 reaction Phase chromatography column, using double distilled water: methanol: acetic acid (74: 24: 2, v / v / v) as mobile phase for isocratic elution, flow rate 1mL / min, column temperature 30 ℃ for Pu'er tea and other types of tea The relevant qualitative detection and quantitative analysis of catechin and gallic acid were performed.
The catechin content of various teas is as follows: green tea> black tea> puer tea; gallic acid content is puer tea> black tea> green tea. The optimum extraction conditions of soluble tea polysaccharides in Pu'er tea are hot water soxhlet extraction for 75min, at this time the content of soluble tea polysaccharides in the extract is high. The UV-visible spectrophotometry was used to measure the absorbance of glucose at a wavelength of 490 nm. Phenol-sulfuric acid colorimetry was used to determine the content of soluble tea polysaccharides in various teas. The content of soluble tea polysaccharides in various teas was: Pu'er tea> black tea> green tea. The chromatographic conditions for lovastatin separation and determination in tea were studied in this paper. A C18 reversed-phase column was used. The ratio of mobile phase was methanol: water = 80: 20, flow rate was 1mL / min, and column temperature was 30. The main peak of lovastatin was well separated from the impurities at ℃; the concentration of lovastatin showed a good linearity in the range of 9.8 to 78.4 μg / mL (R2 = 0.995); the precision and reproducibility were good, and the sample recovery was good. Stable (98.18%).