| Green tea is one of the most widely consumed non-alcoholic beverages in the world. It is generally believed that catechins derivatives are active components responsible for beneficial effects associated with drinking tea. Also, green tea is receiving much attention for specific health claims and because of the presence functional constituents, such as EGCG. In recently years, canned and bottled tea drinks are getting popular worldwide. A suitable product of green tea extract is presumed to have a better taste. And the color of green tea extract, clear greenish-yellow, without any trace of red-brown color have been judged to be very appealing. But it is difficult for the bottled green tea beverages to keep their infusion color and sensory quality during processing and storage. Presently, almost all green tea beverages are derived from dried green tea, which is manufactured by a long-term drying by heating. Such a production process will lead to loss different functional components of green tea fresh leaf, so the liquor color from the dried green tea leaves turns yellow because of adverse heat from processing. In fact, the raw material from different varieties can play an important character in keeping good infusion color, and taste quality. But the research in this field is little, especially, on processing and storage. So the goal of the present study was to examine thermal stability under heat processing condition and long-term stability of quality of different beverages during their storage, and to know some mechanism and characters about different varieties on their manufacture.1. An orthogonal experiment was applied to study the effect of extracting temperature, duration and ratio of tea to water on the quality of fresh green tea juice. The results showed that with the rising temperature and extending extracting duration, the extracted solids yield increased, the color of infusion turned yellow and lightness of infusion decreased, and tea cream increased. The optimum condition of extractionwas as fallows: the raio of tea to water 1:60, temperature 50#,and extraction duration10min. Considering the plucking standard, we found that a bud with three leaves or a bud with four leaves can give a good taste quality, and can keep a good color and sensory quality during heat processing and storage.2. Solids extracting ratio of the Zhenongl39 and Shuigu cultivars are obviously higher than the others under the same extracting conditions. On the other hand, the extracting ratio of caffeine, amino acid and tea polyphonels of Zhenongl39, Shuigu and Biyun were higher than the others tested. Chemical composition is important for taste sensory; according to our results, Zhenongl39, Shuigu and Biyun would be good raw material for green tea beverage.3. The lightness and greenness of beverage decreased during heat processing, whereas yellowness of the liquor increased.The differences of different cultivars are not so obvious. The concentration of tea polyphenols and caffeine did not change corresponding to the change of the color, but the concentration of amino acids in beverage increased during heat processing and protein content decreased. The concentration of chlorophyll decreased during heat processing. Because chlorophyll plays an important role in beverage before heat processing, it is important for green tea beverages to sterilize with the low temperature.4. In the course of storage, changes in color of Zhenongl39, Zhenong23 andJiukeng are relatively slight; and the yellowness of Shuigu, Longjing 43 and yingshuang are stronger than the others. The chlorophyll would be degraded gradually in the course of storing, but because of the lower content after sterilization, at large, the degradation is not so seriouly.The sensory quality of green tea beverage would become more sweet, less bitter and astringent with increasing time of storage. There are some differences in change of color and sensory quality. For example, the infusion colors of Jiukeng, Zhenongl39 and Zhenongl38 were comparatively stea...
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