The Aroma And Processing Of Tea

Water extracts of tea is one of the key indexes of tea quality. And the content of tea polyphenols, amino acids, tea caffeine has close connection with tea quality, determines the color and flavor of tea. In this paper spectrophotometric method was used to study the contents of tea polyphenols and amino acids of 23 tea samples at room temperature and 60℃, in order to find out the leaching rate of them.Water extracts contents of tea polyphenols and amino acids was in accordance with tea grade. That is high contents in top grade green tea and low contents in low level dark tea. The results showed that, the water temperature and infusing time affected the infused tea polyphenols and amino acids in tea soup significantly. During the first 30min of the infusing time, the contens increased rapidly, while after the first 30min, the contents becamed basically stable.White tea is a unique type of famous tea in China, its four main varieties: Baimudan tea, BaihaoYinzhen tea, Gongmei tea and New White tea were studied. The aliphatic degradations hexanal, (E)-2-hexenal, (Z)-3-hexenol, 1-penten-3-ol , especially hexanal has higher concentrations, which may be the main contributors to the fresh and tender aroma characteristic. High content of aromatic compounds such as benzaldehyde, phenylacetaldehyde, benzyl alcohol, phenylethanol makes white tea senses refrigerant. The results showed the aroma components of the four varieties of white tea were similar as a whole with a little difference. The concentration of essential oil in white tea decreased during storage, but still has characteristics of white tea in aroma composition.BiluoZhenzhu is a new formulated oolong tea, which was made from tea leaves of green tea Biluochun camellia sinensis, using the processing technology of oolong tea for reference. This paper studied and compared the aroma components of BiluoZhenzhu and Tieguanyin tea. The results showed that the aroma compositions of the two varieties were similar. They both contained high content of high boiling points compounds, which were nerolidol, indole, a-farnesene and 2-phenylethanol, etc. The results also showed some difference in the total essential oil and aroma compositions, because of the different varieties and areas. Such difference is also in accordance with their sensory quality .