The Studies On IR Spectrum Of Tea Characteristics Of The Different Producing Areas

By standards testing (the sample standardization and the measure standardization), the standard IR spectra of the china famous tea was obtained. In order to investigate the overall characteristics of these tea producing area, a visual, simple method (average deviation) was devised according to the similarity degree calculation method of the similarity science and the analogue method of curves. Using this method, the relation between the average deviation of the tea IR spectra and their latitude was analyzed.The experiment show that: The frequency, intensity and shape of the IR spectrum may appear baseline excursion, aberrance of spectra with the different of testing condition, the sample preparation. In this paper, we analyze the effect of these factors on the quality of the IR spectrum, by using the infrared radiation, the effect of water-vapour may be decreased; by choosing the optimum proportion of sample and KBr and the size of sample at 160 mesh, the IR spectrum has good recurrence.In order to investigate the overall characteristics of tea producing area, we devised a visual, simple method (average deviation) on the Standardized IR spectra to analyze the relation between the average deviation and the latitude of several typical standard teas. The result shows that: The average deviation of the tea with similar latitude and altitude is very small; On the contrary, the average deviation is considerable. The producing area of Xihu-Longjing and tongting-Biluochun have similar latitude and altitude, their average deviation is small. The distance of Taiwan and Fujian is near latitude, so the deviation average of Taiwan-Wulong and Fujian-Tieguanyin is small. The origins of xihu-Longjing and yunnan-Pu'er not only have big difference between latitude but huge altitude difference, so there is a large average deviation. Therefore, there are affinity between the altitude and latitude of the tea producing areas and the average deviation of their IR spectrum.These results show that: although the tea belong to the same variety and have the same characteristics, the tea from different producing areas show delicate difference because of the influence of the environmental factor. We could get the relationships between the producing areas of tea and the altitude and latitude, so the average deviation method would be a powerful method which could provide theoretical basis for the identification of tea.