Study On The Defluoridation Techniques Of Fuzhuan Tea

Fuzhuan brick tea, a kind of dark tea, whose processing material is rather coarse old,tends to enrich fluorine from soil to its old leaves along with the growth process.Long-term drinking high fluorine-content fuzhuan brick tea can lead to fluorosis, accordingly, reduce fluorine content has been one important field of the fuzhuan brick tea processing technology.While a few researchers attempt to reduce the content of fluorine through the improvement of cultivation conditions and change the process methods, there are few reports about reducing the fluorine content of fuzhuan brick tea in by the means of adding food substances. The present study, using the one bud with four or five leaves as raw material, investigate the process of reducing the fluorine content in Fuzhuan tea by adding sugar or milk powder and expect to provide the basis of production theory for low fluorine Fuzhuan Tea. The main results are as follows:(1) Sugar as fluorine reducing agent, adding 5g/kg, 10g/kg, 15g/kg sugar in Fuzhuan Tea processing process, good effect is decline(fluoride reduction rate is higher than 25%): skilling with sugar 10g/kg, fluoride reduction rate is 27.77%; pile-fermentation with sugar 10g/kg,fluoride reduction rates were 27.87%; fungus growing with sugar 15g/kg, fluoride reducing rates were 35.69%. Then the Fuzhuan Tea quailty components analysis, with water extract content, free amino acid content, tea polyphenols content, soluble sugar content, are relatively high, caffeine content and fluorine content are relatively low for the most suitable addition time, the optimum amount treatment. Screened in the pile-fermentation with sugar10g/kg for the optimal fluoride reducing technology, the water extract, caffeine, free amino acids, tea polyphenols, total soluble sugar and fluoride content are 40.10%, 4.10%, 5.14%,14.73%, 4.7%, 71.68mg/kg, respectively.(2) Powder milk as fluorine reducing agent, adding 5g/kg, 10g/kg, 15g/kg powder milk in Fuzhuan Tea processing process, good effect is decline(fluoride reduction rate is higher than 25%): skilling with powder milk 5g/kg, 15g/kg, fluoride reduction rates were 33.90%,25.46%; twisting with milk 5g/kg, 10g/kg, 15g/kg, fluoride reduction rates were 39.10%,30.46%, 37.58%; pile-fermentation with powder milk 5g/kg, 10g/kg, 15g/kg, fluoride reduction rates were 30.09%, 32.81%, 30.27%; fungus growing with powder milk 5g/kg,10g/kg, 15g/kg, fluoride reduction rates were 30.09%, 27.85%, 27.65%. Then the Fuzhuan Tea quailty components analysis, with water extract content, free amino acid content, tea polyphenols content, soluble sugar content, are relatively high, caffeine content and fluorine content are relatively low for the most suitable addition time, the optimum amount treatment.Screened in the twisting with powder milk 5g/kg for the optimal fluoride reducing technology,the tea extract, caffeine, amino acid, tea polyphenol, total soluble sugar, fluorine content are32.53%, 2.84%, 3.06%, 17.02%, 3.68%, 60.52mg/kg, respectively.(3) From the fluorine reducing effect, at the same time and amount of sugar and powder milk, the fluorine reducing agent effect with powder milk is more obvious than sugar. At the skilling, twisting, pile-fermentation with 5g/kg sugar, powder milk 5g/kg, the fluoride content with sugar almost no change, and with milk fluorine reducing rate respectively 33.90%39.10% 30.09%; twisting with sugar 15 g /kg, with powder milk 15 g /kg fluorine reducing rate are 22.02%, 37.58%; pile-fermentation with sugar 10g/kg, with powder milk 10g/kg, fluorine reducing rate are 27.87%, 32.81%; fungus growing with sugar 5g/kg, powder milk 5g/kg,fluorine reducing rate is 24.81% 30.01%, respectively; fungus growing with sugar 10g/kg,milk powder 10g/kg. Fluorine reduction rate of 22.65%, 27.85%. But on the contrary skilling with sugar 10g/kg, with milk powder 10g/kg, the fluorine reducing rate 27.77%, 18.78%;fungus growing with sugar 15g/kg, with milk powder 15g/kg, fluorine reducing rates 35.69%,27.65%.