Black tea: It can inhibit the accumulation of abdominal fat. When it comes to obesity, people immediately think of abdominal fat, and black tea has an obvious effect on inhibiting the increase of abdominal fat. Black tea is made of Aspergillus Niger, which is black as its name implies. In the process of mourning, a kind of Puno component will be produced to prevent fat accumulation. If you want to lose weight with black tea, you'd better drink fresh strong tea. In addition, drink 1.5 liters every day, and drink one cup before and after meals for a long time. Black tea has a long history of production in China, mainly produced in Hunan, Hubei, Sichuan, Yunnan, Guangxi and other places. Black tea can be brewed directly or pressed into pressed tea (such as various brick teas). Their soup color is close to crimson, and their leaves are evenly spread and bright. Black tea is one of the important teas in China. However, due to the physiological characteristics of absorbing and accumulating fluorine, many black tea products have high fluorine content, and long-term drinking has caused chronic "fluorosis" in ethnic areas. Taking Sichuan black tea as the research object, this paper studies the technology and theory of reducing fluorine content in Sichuan black tea by using the knowledge of cultivation, processing, biochemistry and physical chemistry. The results are as follows: (1) The fluorine content of Sichuan black tea is generally high, reaching 663.3~ 1432.5mg/kg. The average value is 986.2 183.6 mg/kg/kg, in which the average fluorine content of Kangzhuan tea is 976.0 169.6 mg/kg, and that of Jinjian tea is 1000.4 204.0 mg/kg/kg, with no significant difference. The high fluorine content of Sichuan black tea is mainly composed of raw materials, especially Zuozhuang tea (112.5 289.8 mg/kg) and Maozhuang tea (11.686). Further research shows that the high fluorine content of Sichuan black tea, the brewing method and the large amount of tea consumed by tea drinkers (18.2 ~ 26.5g/ day) are the main reasons for the high daily fluoride intake of tea drinkers (12.9 ~ 18.2mg/ day). (2) In order to solve the problem of high fluorine content in Sichuan black tea, the author used the method of dynamically monitoring the fluorine content of black tea raw materials and harvesting them in time to obtain low fluorine raw materials and trial-produce low fluorine black tea products, and combined the optimized blending and defluoridation technology with adsorption to reduce the fluorine content in Sichuan black tea. The results showed that the fluorine content of low fluorine brick tea and Jinjian tea were 432.4±65438±02.7mg/kg/kg and 485.3±65438±00.8mg/kg/kg, respectively, which were 54.0% and 53.7% lower than those of Sichuan black tea products in the market. Then, using low-fluorine raw materials as ingredients, the proportion of Sichuan black tea was optimized by multiple linear mathematical model, and I-type low-fluorine brick tea and Jinjian tea were trial-produced. The fluorine contents were 360.5 4.4 mg/kg and 373.310.1mg/kg, respectively, which were 65,438 lower than those of low-fluorine brick tea and Jinjian tea directly processed with low-fluorine raw materials. At the same time, by optimizing the proportion of existing ingredients, Type II low-fluorine brick tea and Jinjian tea were trial-produced, and their fluorine contents were 57 1.7 10.7 mg/kg and 572.7 15.0 mg/kg, respectively, which were 39.2% and 45.3% lower than those of Sichuan black tea products on the market. In addition, from 1 1 kinds of effective defluoridation materials, two high-efficiency defluoridation materials (LSG and YSZ) were selected for adsorption defluoridation. The results show that LSG and YSZ can significantly reduce the fluorine content of tea soup during boiling, and the defluorination rate is as high as 40%. However, the addition of alkali and salt is not conducive to reducing the fluorine concentration in tea soup. (3) The product quality after defluorination by three defluorination technologies was further analyzed. The results show that the quality of Sichuan black tea trial-produced by defluorination technology and optimized defluorination scheme is better than that of the control sample, especially the water extract content is higher. Among them, the water extract contents of low-fluorine brick tea and Jinjian tea trial-produced by dynamically monitoring the change of fluorine content in raw materials and timely harvesting low-fluorine raw materials are 35.565438 0% and 35.93%, respectively, and the water extract contents of Type I low-fluorine brick tea and Jinjian tea trial-produced by optimizing ingredients are 29.33% and 28.89%, respectively, which are superior to the commercially available Sichuan black tea products. At the same time, the experimental results show that the low-fluorine black tea product has boiling resistance and is superior to the control sample in sense. Therefore, Sichuan black tea products produced with low fluorine raw materials and Sichuan black tea products trial-produced by optimized blending method belong to low fluorine and high quality black tea products. At the same time, the quality of tea soup after fluoride removal by adsorption defluoridation technology was identified. Although some quality indexes of tea soup are slightly worse than the control, the sensory quality of tea soup is similar to that of the control sample, which further verifies the feasibility of reducing fluorine content in Sichuan black tea by adsorption fluorine reduction technology. (4) Using the principle and method of adsorption equilibrium theory and adsorption kinetics, the adsorption properties of LSG and YSZ for fluorine in tea soup were discussed. Under the experimental conditions, the adsorption of fluoride in tea soup by LSG and YSZ accords with Langmuir equation, and the adsorption of fluoride by LSG belongs to chemical adsorption, and the maximum saturated adsorption capacity is10.627 mg/g; /g； The adsorption of fluoride by YSZ belongs to physical adsorption, and the maximum saturated adsorption capacity is13.624 mg/g/g. In the tea soup system, adding salt can significantly reduce the adsorption of fluoride by YSZ, but it has no significant effect on LSG. Although the adsorption amount of fluorine on YSZ decreases with the increase of adsorption time, before the adsorption amount of fluorine on YSZ reaches equilibrium, its adsorption kinetics can still be fitted by quasi-second-order velocity equation, but the fitted data are different from the measured data. The adsorption kinetics of fluoride in tea soup by LSG can be fitted by quasi-second-order velocity equation.