Eff2ect Of Ca²⁺ In Water On The Green Tea Infusion Quality Components And Turbidity Production

As a healthy drink for preference, tea is liked for its excellent colour, taste, amora and healthfunctions. Pepole already knew the importance of water on the tea, so ‘Longjing Tea with HupaoWater’ was a usual collocation. This reseach has the order to find out the influence of metal ions in thewater. First, a kind of metal ion which has the greatest influence to the tea infusion is found out. Thismetal ion is Ca²⁺. Then comprehensive studies on the effections of the ion to tea infusion are done, tofind out which quality component is effected most greatly. Finally, the correlation analysis has beendone between turbidity and chemical components. The major results are as follows:1. Three kinds of metal ions are chosed to brew tea powder. They are Ca²⁺, Mg2+and Al3+. Thenphysical and chemical components are detected. Ca²⁺has the greatest influence on turbidity andaorma of the tea infusion, even greater than the mixture of Mg2+and Al3+. So Ca²⁺and turbidity arechosed to be the study objects in this paper.2. The studies are ordered to make sure the effect of Ca²⁺on quality components in the teainfusions, and on the extracions of the tea. Results show that Ca²⁺has great effect to tea infusions onorganic acids, but has little effect on proteins, polyphenols, flavonoids, total carbohydrate, aminoacids, and so on. The different concertrations of Ca²⁺solutions have great effect on the extracting oftea on polyphenols, catechines, proteins and mental ions, but little effect on amino acids, flavonoidsand caffine. When the concertration of Ca²⁺is40mg/L, it has great effect on the extracting of oxalicacid, quinic acid, malic acid and citric acid, and the extraction decreased significantly.3. Some kinds of tea are detected to find out the containing ranges of organic acids. Differenttreatments of pH and temperature have important influence on organic acids extraction. The resultsshow oxalic acid, tartaric acid have significant correlation with turbidity. Statistical methods are usedto do correlation analysis between turbidity and orgnic acids in the tea infusions with Ca²⁺.4. One of the study objects is a kind of organic acids called oxalic acid. Oxalic acid, polypenols,proteins are used to have minxture simulation experiment, to find out the influence of Ca²⁺. Theresults show that polyphenols and proteins can form comlex. When oxalic acid and Ca²⁺are addedtogether, the complex is reduced. Infusion with oxalic acid and Ca²⁺has lots of turbidity. And theturbidity is not reduced when polyphenols and proteins are added.