Study on variation of metal elements during Pu 'er tea fermentation

The variations of metal elements during pile-fermentation of Pu'er tea were studied by using tertiary sun-dry tea as raw materials and setting different turning piles. The results showed that with the increase of turning piles the content of trace element Iron and Manganese increase with the spiral tendency,and increase respectively 77% and 13%,the content of trace element Zinc show an increasing trend,and increase33%,the content of trace element Copper decrease with the spiral type,and decrease 4% at the end of fermentation. The content of heavy metal Cadmium and Chromium increase with the spiral type,and increase respectively 12%,16%,the content of heavy metal Lead show an increasing trend,and increase 18%,the content of heavy metal Arsenic firstly decrease then increase 8% at the end of fermentation. The total rare earth oxide showed an increasing trend,and increase 1.1 times at the end of fermentation. The results showed that the variation of metal elements was significantly in the pile-fermentation process of different turning frequency and fermentation layer,all these provide some certain technological support for product quality and safety during Pu'er tea fermentation process.