Analysis And Evaluation Of Tea In Lin'an

In this paper, the quality of tea in different producing areas and the main tea varieties in Lin'an was analyzed, and the comprehensive evaluation was made from the aspects of region,altitude, variety and processing methods, providing the scientific theoretical basis for Lin'an tea processing enterprises to select tea resources and develop high-quality tea products. Therefore, it will lead to increasing the Lin'an tea brand impact and market competitiveness.In this experiment, quality indexes (water extracts, protein, vitamin C and free amino acid),antioxidant activities (tea polyphenol, total flavonoids, reducing power and metal chelating activity) and components of aroma in 17 samples of green tea and 10 samples of black tea were analyzed. The results were as flowed:1?There was no significant difference in the water extracts content, protein content and total free amino acid content between green tea and black tea (p>0.05). But there was a highly significant differences (p < 0.01) between vitamin C content, green tea had higher vitamin C content compared with black tea. It was no significant difference in water extracts content, protein content and vitamin C content between green tea and black tea from different region and altitude (p> 0.05). There was no significant difference in water extract content and protein content between processing method of heavy fermented and light fermented in black tea (p>0.05), and the light fermented black tea had higher vitamin C content.2?The contents of tea polyphenols and total flavonoids and reducing power of green tea and black tea were significantly different (p <0.05). Green tea had higher tea polyphenols and reducing power, while black tea had higher content of flavonoids. There was no significant difference in metal chelating activity(p> 0.05). There was no significant differences in the contents of tea polyphenols, flavonoids and metal chelating activity between Shangwo, Tongkeng and Dongkeng,and the green tea produced by Shangwo had stronger reducing power. The contents of tea polyphenols, flavonoids and reducing power in green tea at different altitudes had no significant difference, green tea at 400-500 m altitude had the strongest metal chelating activity. Compared with other producing areas, the contents of tea polyphenols, total flavonoids in Lin'an Dashan tea were lower, and the reducing power and metal chelating actvity were weaker. There was no significant difference in the content of tea polyphenol, total flavonoids and metal chelating activity between processing method of heavy fermented and light fermented in black tea, but the reducing power of light fermented black tea was significantly higher than that of light fermented black tea.3?There were significant differences in the relative contents of 15 aroma components between green tea and black tea. The highest content of green tea was Oxime-,methoxy-phenyl-(7.14%), while the highest content of black tea was 2,6-Octadien-1-ol,3,7-dimethyl-, (E)-(20.96%). 19, 14 and 14 kinds of volatile components were identified in green tea produced in Shangwucun, Tongkeng and Dongkeng respectively. Green tea produced at the altitude of 40-100 m, 400-500 m and 500-700 m was identified respectively 21, 22 and 16 kinds of volatile components. Qingliangfeng produced the highest content of 2,6-Octadien-1-ol,3,7-dimethyl-. (E)- in black tea, reaching 31.45%. There was significant difference in the total volatile components between processing method of heavy fermented and light fermented in black tea, and light fermented black tea had higher contents.4?Region and altitude had little impact on the qualities of green tea and black tea. But for black tea, from the quality point of view. light fermentation was a more worthy of recommended processing method.