Welcome to Journal of Tea Science,Today is

Journal of Tea Science ›› 2011, Vol. 31 ›› Issue (4): 349-354.doi: 10.13305/j.cnki.jts.2011.04.011

Previous Articles     Next Articles

Status of the Total Amount of Rare Earth Oxides in Tea and Its Leaching Characteristics

SHI Yuan-zhi, HAN Wen-yan, MA Li-feng, FANG Li   

  1. Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
  • Received:2010-11-23 Revised:2011-04-18 Online:2011-08-15 Published:2019-09-09

Abstract: In order to figure out the status of total amount of REE oxides(∑REOs) in tea and its leaching characteristics, the statues of ∑REOs in 1245 tea samples from 2007 to 2010 were statistical analyzed, and the leaching characteristics on the different ∑REOs with different processing technology were studied. The results showed that the Median of the ∑REOs in Chinese tea was about 2mg/kg, and the ranges were from ND to 13.80mg/kg, about over 90% of tea were under 5mg/kg. The ∑REOs in over half of Oolong teas were more than 2mg/kg, but for the other tea such as green tea, scented tea, less than 30% of those teas were more than 2mg/kg. When the tea was grinded, the leaching rate of the ∑REOs was increased significantly than the original tea. And the processing technology maybe was the major factor to impact on the leaching rate of the ∑REOs. There were some rules about the leaching rate followed by low to high: needle-shaped tea< flat-shaped tea (such as Longjin tea)< Curl-shaped tea < powdered tea. The ∑REOs was highest in the first brew, and then was decreased along with the 2nd and the 3rd brews. The Powdered Oolong tea has the highest leaching rate about the ∑REOs, the leaching rate was about 60%, but even the ∑REOs in the powdered Oolong tea has reached to 6mg/kg,the ∑REOs in the brew still under the limited value about the standard in drinking water. The needle-shaped tea has the lowest leaching rate about the

Key words: tea, ∑REOs, leaching rate

CLC Number: