| A new-type tea beverage fermented by Saccharomyces rosei 1403 has been researched and developed. The variations of catechins and organic acids during the fermentation process and the stability of catechins in acid buffers were investigated. The activity of the fermented liquid on bacteria from stomach and intestines, and the effects of the compressed tea infusion on some pancreatic enzymes were studied too. The results were concluded as follows:1. During the fermentation of green tea infusion, the pH value decreased to 2.31 from 5.16. The contents of sucrose and fructose decreased from 137.5mg/ml to 13.0 mg/ml and 61.6 mg/ml to 16.6 mg/ml, respectively. However, in the first 36 hours of fermentation, the content of reducing sugar increased from 11.5 mg/ml to 83.9mg/ml, then it turned to decrease gradually. The yeast (Saccharomyces rosei 1403) grew well in the culture medium containing green tea.2. The content of catechins in the fermentation substrate changed from 1.19 mg/ml to 0.46 mg/ml, and the uptake and accumulation of the catechins in the yeast cells was about 1333.On g after 60 hours of fermentation. Which suggested that the main factors caused the contents of catechins down were that some catechins was uptaken by yeast, some other formed complex between catechins and catechins or with organic acids. Besides the forming of complex, some catechins degraded in the last fermentation stage.3. A lot of organic acids were produced in the fermentation, which caused the decreasing of pH value. Acetic acid and the acids in TCA cycle such as succinic acid, isocitric acid, and L-malic acid all increased. They increased 16.78, 1.85, 8.53 and 2.77 times than the initial ones, respectively.4. The stability of the catechins was dependent on the pH value of the buffers. Catechins were stable in the buffer in range of pH 3.6 to 5.6. But they became unstable when the pH value of the buffer was below 3.0. The reason might be that some catechins combined with acid or formed reversible complex in the acid solution. It was very interesting that the complex could release most of catechinswhen the pH of buffer was adjusted to 5.6 for 3 hours. But the degradation of catechins was much more in the more acidic buffer.5. The content of the catechins in compressed tea was less than that of in green tea, but the organic acids content was much higher than that of in green tea, which suggested that many kinds of bacteria and yeast changed the components of compressed tea.6. The synergy of catechins and acids could inhibit the growth of E. coli and S. aureus. The fermented tea solution could improve the growth of L.bulg. and B.bifudwn., the effects might come from catechins.7. All of the three kinds of compressed tea tested could promote the activities of pancreatic proteinase and a-amylase, and inhibit the activity of lipase. Especially Yunnan compressed tea showed the highest promotion, the activities of the two enzymes improved by 15.6 and 17.2 times compared with the control. The effects of compressed tea on activities of pancreatic enzymes showed some relationships between polyphenol and organic acids.
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