The Determination And Value Of Trace Elements In Different Types Of Oolong Tea

In Oolong tea,its nutritional and health effects are not only related to its rich organics,but also have a very important relationship with its own rich trace elements.As other tea,oolong tea also contains a lot of trace elements,so it is meaningful for us to study the content of trace elements in Oolong tea.This research uses the ICP-MS and atomic absorption spectrometry in determine the content of 8 kinds of trace elements in different types of Oolong Tea,including Fe,Mn,Zn,Cu,Se,Co,Mo and Pb.The Oolong tea included different varieties of Oolong tea,the oolong tea produced in different areas,the different processing methods of Oolong tea,and the different positions leaf in Oolong tea varieties.Through determining the content of trace elements in Oolong tea and in tea liquor,we can use the result to determine the effects of drinking Oolong Tea on human health.The results:(1)In different varieties of Oolong tea,the conetent of trace elements have some difference.The content of different kinds of trace elements in Oolong tea may always have the fowllowing rule:Mn>Fe>Zn>Cu>Pb>Co>Se>Mo;(2)In different varieties of Oolong tea,the dissolution rate of trace elements have some difference,and the different trace elements have different dissolution rate.The dissolution rate of Fe,Mn,Cu and Se this four trace elements are smaller than the others,and the remaining elements' dissolution rate is unstable.;(3)The contents of trace elements in different vatieties are all within the human body's acceptable range.As for the content of Pb,it is within the standards' limits;(4)The Oolong tea samples from different regions have different content of trace elements,the content of trace elements in Oolong tea sample from Quanzhou Qingyuan mountain area is much more than the one from Pinghe Daqin mountain.But in dissolution rate of trace elements,the samples from this two areas are similar,and the total amount of trace elements in Oolong tea soup in Quanzhou Qingyuan Mountain area will be larger than that of the Oolong tea;(5)No matter which areas' Oolong tea,the content of Pb are all within the standards' limit,and the dilution in the tea liquor is far less than the human bodies' withstand.Therefore,the Oolong tea made in these two areas are meaningful to human health in the trace element supplement;(6)In the Oolong tea of different processing methods,the content of Zn?Cu?Co?Mo?Se and Pb this 6 kinds of trace elements do not have great difference,but Fe and Mn this two elements in some varieties will be some differences.In the dilution rate of trace elements in Oolong tea liquor,the dissolution rate of Fe and Mn in two processing methods are similar,and smaller than others,and some of the rest trace elements have higher dissolution rate in northern Fujian process method,and some are higher in southern Fujian process method.But taken together,the southern Fujian process method's Oolong tea have higher dissolution rate.;(7)No matter what kind of processing method,the dissolution of trace elements in tea soup will not cause harm to human health,and the content of Pb are also within the limit of the standard;(8)In different leaf positions of Oolong tea,The contents of Cu,Mo and Se in different leaf positions were different,and the contents of Zn and Co from the first leaf to the fourth leaf were decreasing.The distribution of Mn in the first leaf to the fourth leaf is increasing,and the content of Fe in the different leaf position is relatively irregular.The content of Pb in the stem is the highest,and the distribution in other positions is average.From fresh leaves to refined tea,the content of trace element in fresh leaves will be further reduced,especially the Pb,and then for the health of the human body will be more favorable;(9)The correlation between the biochemical compositon and the trace elements in tea:the content of tea polyphenols was negatively correlated with the content of Fe,and there was a significant negative correlation with the contents of Zn and Cu.The content of amino acids was positively correlated with the contents of Zn and Cu.The content of caffeine was related to the content of Co and Mo,the content of water extract were significantly positively correlated with the content of Fe element,and there was a significant negative correlation with the content of Cu element.The content of flavonoids were significantly negatively correlated with the content of Fe,there was a significant positive correlation between the content of tea veins and the elements of Co,Mo and Se,and the contents of tea flavonoids were positively correlated with the contents of Fe,Zn and Co.There was a significant positive correlation between the score of sensory evaluation and Zn,Mo and Mn,and negatively correlated with the content of Se;(11)The correlation between the biochemical composition and trace elemetns in tea soup:there were significant positive correlations between the contents of tea polyphenols and the content of Mn.The content of amino acids was positively correlated with the contents of Cu,Zn,Pb and Fe,and there were significant correlations with Se,Mo and Mn,the content of flavonoids was positively correlated with the content of Mn.There was a significant positive correlation between the conductivity and the contents of Co,Se,Zn and Mn,and was positively with the content of Cu and Pb,the pH was positively correlated with the contents of Cu,Mo and Fe.Throug the detection and analysis of the content and the dissolution rate of trace elements in different types Oolong tea,this paper will provides a theoretical basis for healthy method of drinking Oolong.