Black tea is fermented by Aspergillus Niger. In this fermentation process, black tea will produce a component called Punol, which has a significant effect on preventing fat accumulation.
To lose weight with black tea, it is best to drink fresh strong tea. Moreover, dieters should insist on drinking 1.5 liters of black tea juice for at least one day, and drink one cup before and after meals, and insist on drinking for a long time. Bud, Yongjiang Baimaojian, Wenzhou Tanghuang, Anhui Huangliang Tea, Guangdong Dayeqing Tea and Haima Gongcha.
The raw materials of black tea are coarse and old, and it usually takes a long time to accumulate and ferment in the process of processing, so tea leaves are mostly dark brown, hence the name. Black tea is mainly consumed by some ethnic minorities, among which Tibetans, Mongolians and Uighurs especially like to drink black tea, which is a necessity in their daily life. In the production process, the technology of black tea is unique. Black tea has a wide origin, many varieties and different colors, such as black brick, Huazhuan and Fuzhuan made of Hunan black tea, blue brick made of Hubei old green tea, Liubao tea in Guangxi, Xilu tea in Sichuan, pressed tea, flat tea, square tea and round tea in Yunnan.
The famous black teas are Xiangjian, Hunan Black Tea, Laoqing Tea, Sichuan Border Tea, Liubao Tea, Pu 'er Tea, Black Brick Tea, Fuzhuan Brick Tea and Kangzhuan Tea.
Black tea is a kind of tea, which has all the biochemical characteristics of other teas. However, because black tea is different from other teas in the selection of raw materials and processing technology (fermentation and blooming), the composition and proportion of biochemical components of black tea and the resulting pharmacological effects are special, which is the relationship between * * * and personality.
There is no doubt that drinking tea is beneficial to human health, but what kind of tea to drink needs to be chosen according to the actual situation of the individual. Tea is essential in daily life. Drinking tea can not only satisfy the demand of physiological thirst quenching, but also prevent or treat diseases, killing two birds with one stone.
Tea experts Chen Zongmao and Liu have done a lot of work in studying the relationship between Pu 'er tea and human thirst quenching. In his view, among the functional components of Pu 'er tea, except tea polyphenols and theaflavins, trimethoxy derivatives with dimethoxy deterioration are all substances with strong antioxidant effect. A large number of clinical experiments have proved that the tea formed by microorganisms participating in the stacking fermentation process has different functions because of its different components from red and green tea. It has remarkable effects in reducing blood fat, blood pressure, blood sugar, weight loss, preventing cardiovascular diseases and resisting cancer.
(1) tea polyphenols
1. Tea polysaccharide brick tea has the highest content and the strongest activity.
According to the determination, the content of tea polysaccharide increases with the aging of tea raw materials. The content of tea polysaccharide in grade six tea is about twice that of grade one tea. In addition, the content of tea polysaccharide in different tea leaves varies with different processing methods. When fresh leaves with the same tenderness are processed into green tea, black tea and black tea respectively, the content of tea polysaccharide in black tea is the most, followed by green tea and the least.
Tea polysaccharide complex is usually called tea polysaccharide, formerly known as lipopolysaccharide, and it is a complex and diverse mixture of components. Former Soviet scholar b? A Samdak first reported the pharmacological study of tea polysaccharide, and studied the extraction and anti-radiation function of tea polysaccharide in 1962. Further research later showed that tea polysaccharide is an acidic glycoprotein, which combines a large number of mineral elements, mainly containing trace elements such as calcium, magnesium, iron, manganese and a small amount of rare earth elements.
Scientists have found that it is its advanced structure that determines the biological function of tea polysaccharide. X-ray diffraction showed that the activity of lentinan and polysaccharide pleat was lost after adding urea or dimethyl alum. This fully confirmed the significant influence of host configuration on polysaccharide activity. The polysaccharide chain is huge or slender. If it is active, there must be an active center (or active fragment). At present, scientists have made some achievements in studying the structure of polysaccharides, but there is still a big gap compared with protein and nucleic acid research.
Because of the tenderness of raw materials and processing methods, the changes of high polysaccharide content and its components in black tea have attracted more and more attention of scientists. The results of age determination of patients with tea polyphenols in several teas show that black tea has the highest content of tea polyphenols, and its component activity is stronger than other teas. This is because in the fermentation process, due to the action of glycosidase, protease and hydrolase, relatively short sugar chains and peptide chains are formed. Studies have shown that short peptide chains are more easily absorbed and have stronger biological activity, which may be one of the reasons why fermented tea, especially black tea polysaccharide, has better hypoglycemic effect than other series.
Sugar is an organic compound widely distributed in nature, and it is also an important information substance of important biopolymer mixtures. Clinically used as tea polysaccharide to treat epidemic bacteria, it has a series of health care functions such as lowering blood sugar and blood lipid, improving immunity, anticoagulation, thrombosis, hypoxia tolerance, ultraviolet and X-ray radiation resistance.
However, tea polysaccharide is a physiologically active substance, which is easily soluble in water, insoluble in high concentration organic solvents, and easily loses its activity at high temperature. Too strong acidity or too weak alkalinity will partially degrade polysaccharides. Therefore, it is technically difficult to separate active tea polysaccharides from tea.
2. Tea polysaccharide has many pharmacological functions.
As mentioned earlier, tea polysaccharide is a complex and diverse acidic protein, which combines a large number of mineral elements. Although scientists have done a lot of work in the clinical trials of polysaccharides on human body, the mechanism of the relationship between the complex structure of polysaccharides and their functions in vivo is not very clear, and the research on the solution conformation and crystal structure of polysaccharides is almost blank, and there are still many problems in the determination methods. Some special clinical trial results of polysaccharide in human body are as follows:
⑴ Tea polysaccharide can lower blood sugar.
At present, there are three effective components of tea to reduce blood sugar: tea polysaccharide, tea polyphenols, diphenylamine and so on. Among them, tea polysaccharide is the main component. Tea polysaccharide tastes sweet and pure, and the old black tea stored for many years is getting sweeter and sweeter, which may be related to the content of tea polysaccharide.
Hypoglycemic mechanism of tea polysaccharide: epinephrine, thyroxine and glucagon can increase blood sugar and accelerate the decomposition of hepatic glycogen, while only insulin can reduce blood sugar, so the hypoglycemic effect of tea polysaccharide may also be related to its protection and stimulation of insulin cell secretion. Li believes that tea polysaccharide can reduce the blood sugar concentration of alloxan-induced hyperglycemia mice, and at the same time, it can greatly increase liver glycogen, which shows that the effect of tea polysaccharide on glucose metabolism is similar to that of insulin.
Island? Cells are easily destroyed by free radicals such as alloxan. Is alloxan diabetes caused by alloxan on insulin? It is caused by selective and specific necrosis of cells. ICR mice were given tea polysaccharide for 4 weeks, and then the membrane was made with alloxan for 3 days. After that, the activities of SOD and GSH-Px in liver increased, while the content of MDA decreased. Tea polysaccharide can eliminate the damage of excessive free radicals in the body by improving the antioxidant function of the body.
On the other hand, Wu Jianfen and others found that unique can enhance the enzyme activity of hepatic glucokinase. Glucokinase is an isoenzyme of hexokinase, which mainly exists in mature liver parenchyma cells and islets. In cells, it is regulated by insulin, which catalyzes the conversion of glucose into glucose 6- phosphate, and then forms glycogen, thus lowering blood sugar. Tea polysaccharide can effectively reduce blood sugar by antioxidation and enhancing glucokinase activity.
In addition, the hypoglycemic mechanism of tea is also related to other enzymes. Yin Xuezhe and others reported that green tea extract is? -Amylase also has a certain inhibitory effect (the inhibitory rate is 2 1%), which can delay or slow down the digestion and absorption of sugar in the intestine, increase its excretion, and thus reduce postprandial hyperglycemia. As for the hypoglycemic mechanism of tea pigment, Tao Chunxiang and others think it may be related to improving hemorheology and platelet aggregation, reducing whole blood viscosity, improving systemic microcirculation and tissue metabolism. Indirectly improve the function of insulin cells, thus reducing blood sugar.
⑵ Hypolipidemic effect of tea polysaccharide.
Hyperlipidemia is the main cause of human cardiovascular and cerebrovascular diseases. The results showed that the concentration of 0.2 ml tea polysaccharide was 4. After mg/ml was injected into the abdominal cavity of each mouse for 65438 0.2 hours and 24 hours, the serum triglyceride in the administration group decreased by about 65438 0.8%. After 65438 0.2 hours, the serum cholesterol content in the treatment group was about 65438 0.5% lower than that in the control group, and it was about 5.0% lower after 24 hours, but none of them reached a significant level. Zhou Jie's experiment also got the same result. Triglycerides and serum cholesterol decreased slightly, but did not reach significant levels. At the same time, it was found that the high-density lipoprotein cholesterol content increased by 7. 1% at 12 hours and 15% at 24 hours after administration. The increase of high-density lipoprotein cholesterol content shows that tea polysaccharide can reduce serum low-density lipoprotein cholesterol, which can make cholesterol enter blood vessels and cause atherosclerosis. Because it can enhance the excretion of cholesterol through the liver. Tea polysaccharide can also combine with lipoprotein esterase, promote lipoprotein esterase to enter the arterial wall, and play an anti-atherosclerosis role.
From May 1900 to May 199 1 May, the General Hospital of the Chinese People's Liberation Army observed the situation of 55 hyperlipidemia patients among 155 cadres in a cadre sanatorium. After taking black tea 180 days (3 grams per day), 50 of them drank black tea, and their blood lipid content decreased obviously. LPO is a kind of peroxide produced by polyunsaturated fatty acids through enzymatic pathway. The main damaged parts are biofilm and subcellular organelles, which affect cell function. Clinical data show that the content of plasma lipid peroxide (LPO) in patients with atherosclerosis is increased. It can be proved that black tea can reduce LPO activity, reduce the incidence of coronary heart disease and delay aging.
⑶ Tea polysaccharide has anticoagulant and antithrombotic effects.
Thrombosis mainly includes three stages: ① platelet adhesion and aggregation; ② Blood coagulation; ③ Dissolution of cellulose protein. Tea polysaccharide can obviously inhibit platelet adhesion and reduce blood viscosity. Wang Shuru and others reported that oral administration of 50mg/kg in mice prolonged the clotting time by 65438 09%. The dosage of 37mg/kg can prolong the prothrombin time of rabbits by 40% and inhibit the experimental thrombosis of rabbits. Therefore, tea polysaccharide can not only anticoagulate blood, but also play an anti-thrombosis role. Tea polysaccharide has obvious anticoagulant effect in vivo and in vitro, and reduces the number of platelets and prolongs the coagulation time, thus affecting thrombosis. In addition, tea polysaccharide can also improve the dissolving activity of cellulose protein. It can be seen that tea polysaccharide may act on all aspects of thrombosis.
⑷ Effect of tea polysaccharide on immune function.
After tea polysaccharide was separated, its humoral immunity and cellular immunity were detected. The results show that it can obviously enhance biphasic immunity, and at the same time, it has the trend of reducing blood sugar, serum cholesterol and triglyceride, which is of great significance for preventing and treating senile degenerative diseases such as diabetes and cardiovascular diseases, and can also improve the immunity of the elderly.
A large number of pharmacological and clinical studies have found that the marketing ways and approaches of natural tea polysaccharides to the immune function of the body mainly include: ① activating macrophages: tea polysaccharides extracted from Echinacea purpurea, Bupleurum chinense, Ganoderma lucidum, Tremella fuciformis and other plants all show this function. Golden flower in fuzhuan tea flower? Ascomycetes coronaria? Its pattern is only found in precious medicinal materials such as Ganoderma lucidum, which may have its mystery and needs further study and discussion. ② Activation of reticuloendothelial system: The reticuloendothelial system in organisms has the function of phagocytizing and expelling aging cells, foreign bodies and pathogens, and its activity is usually determined by carbon particle clearance method. Such as licorice polysaccharide and Eucommia ulmoides polysaccharide. ③ activate T and B lymphocytes; Lentinan is a typical T cell activator, which can promote the production of T lymphocytes in specific cells in vitro and in vivo. And improve its killing activity ④ activate complement: there is a group of protein series with zymogen activity in blood, which is called complement in medicine. It can kill pathogenic microorganisms or assist and cooperate with phagocytes to kill pathogenic microorganisms. ⑤ Promote the production of various cytokines (interferon, interleukin, tumor necrosis factor). These results are consistent with the research results of tea polysaccharide.
5. Other biological activities of tea polysaccharides
Scavenging Effect of Tea Polysaccharide on Alkyl Free Radicals: Tea Polysaccharide (TPS) is an acidic glycoprotein bound to protein, and its polysaccharide is composed of arabinose, xylose, ribose, glucose and galactose. In D- deoxyribose-iron system, TPS8.5- 170 mg/L. -OH is 5.5%-74.7%. Therefore, tea polysaccharide has many biological functions, such as anti-radiation, anti-tumor, anti-virus, enhancing immunity, lowering blood pressure, reducing blood lipid, resisting hypoxia, increasing coronary blood flow and so on.
Wang Dinggang and others injected tea polysaccharide into the duodenum and abdominal cavity of SD rats and mice respectively. The results show that tea polysaccharide has obvious effects of lowering blood pressure, slowing heart rate, increasing coronary flow, prolonging survival time (under hypoxia) and resisting ultraviolet rays and X-rays.
In the depths of black tea stored for many years, there is a special kind of insect (whose name is unknown at present). Tea bug? It only exists in the depths of tea piles under pressure and lack of oxygen. Tea bug? Larvae feed on tea, and their bodies are white, tender and round since childhood. Whether this is related to the anti-hypoxia effect of tea polysaccharide in black tea is still a mystery.
Tibetan areas are located in the plateau, and human beings live in the environment of hypoxia and strong ultraviolet rays. Whether the high-content tea polysaccharide unique to this crude old tea has played a role here is also a question worthy of our in-depth study.
(2) Special amino acids
? -Aminobutyric acid is a non-protein amino acid, which widely exists in animals and plants. Under anaerobic conditions, fresh tea leaves can convert glutamic acid into? -Aminobutyric acid, which is basically consistent with dark tea fermentation, batch fermentation and storage conditions. Does black tea form a lot in this processing technology? -Aminobutyric acid or its products produced by microbial (fungal) metabolism (aminobutyric acid widely exists in animals and plants) have not been reported in detail at present.
? -Aminobutyric acid has many physiological functions for human body, and can be used as raw material for manufacturing functional foods and medicines. Research proves that? -Aminobutyric acid can obviously lower blood pressure, improve cerebral blood circulation, increase oxygen supply and improve brain cell function. It has also been reported that GABA can improve vision, lower cholesterol, regulate hormone secretion, relieve ammonia poisoning, improve liver function, activate renal function and improve menopausal syndrome.
(3) Tea pigment
The main components of dark tea soup color are theaflavins and thearubigins, which are the products of microbial oxidation and condensation of tea polyphenols and one of the main physiological active substances of tea.
The results show that theaflavin is not only an effective free radical scavenger and antioxidant, but also has many physiological functions such as anticancer, antimutagenic, antibacterial and antiviral, improving and treating cardiovascular and cerebrovascular diseases, treating diabetes and so on.
Experiments show that theaflavins have obvious antibacterial effects on Botox, Enterobacteriaceae, Staphylococcus aureus, Capsella and Bacillus cereus. The antibacterial effect may be related to the fact that black tea is not easy to deteriorate.
In addition, theaflavins have a certain inhibitory effect on the invasion of influenza virus, and it is also found that theaflavins can inhibit the infection of rotavirus, and also have a certain effect on bovine virus and coronavirus.
The effect of theaflavins on cardiovascular and cerebrovascular diseases is also a research hotspot in recent years. Lou Fuqing and others found that theaflavins have obvious anticoagulant, fibrinolytic, platelet adhesion and aggregation prevention, inhibition of arterial smooth muscle cell proliferation, and can also reduce red high-density lipoprotein in high-fat animals in leisure time, which has a significant inhibitory effect on ACE enzyme. Has antihypertensive effect.
(4) Mineral elements
Mineral elements are mainly concentrated in mature leaves, stems and stalks. The raw materials of black tea are older, and the content of mineral elements is higher than other teas.
The fluorine content is the highest among all plants. The roots of tea trees absorb fluorine from soil in the form of fluoride-aluminum complex ions, which mainly accumulate in tea leaves. The fluorine content of old leaves is 12-36 times that of young leaves. Fluorine has obvious effect on preventing dental caries and osteoporosis in the elderly.
It is an essential component of human glutathione -px, which can stimulate the production of immune proteins and antibodies, enhance the body's resistance to diseases, and play a significant role in treating coronary heart disease and inhibiting the occurrence and development of cancer cells. Tea should also be concentrated on mature leaves. Wuling Mountain has fertile soil, and the black tea produced is a typical natural rich tea. The content of tea can be as high as 3.8-6.4mg/kg (generally below 0.16 mg/kg).
(5) Tea saponin
Tea saponin is widely distributed in all parts of tea trees, most of which are roots of old leaves. Tea saponin has the functions of hemolysis, cholesterol reduction, antifertility, antibacterial, snail control, anticoagulation, sedation, anticancer and blood pressure reduction.
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