| Pu-erh tea is not only have profound culture; unique style and on human health play an important role, is a kind of healthy drinks, known as the “beauty tea”, “slimming tea”, “longevity tea”. Pu-erh tea has attracted people from all walks of life off, and his demand is greatly improved that the traditional processing methods due to the time-consuming, has been unable to meet the people’s increasing demand. This has a series of problems, such as the demand for a large amount of manpower and material resources, high cost of tea processing, environmental safety and health conditions are not standard, as well as large security risks. These problems have led to the establishment of an efficient, safe, and good economic benefit of the new processing method. Enzyme preparation for tea making technology can solve these problems to a certain extent, because it is a mild, safe environment in which to play a catalytic role, to maintain the nutritional value of tea, do not increase adverse by-products, and can be artificially controlled enzyme activity, in a short period of time to promote tea physical and chemical changes. Based on the characteristics of enzyme and the characteristics of microbial fermentation, in order to achieve fast and high quality fermented tea, this study designed three kinds of fermentation methods. In order to study the three kinds of fermentation(exogenous enzymes, single bacteria, enzymes and bacteria) effect on liquid fermentation of Pu-erh tea, in this experiment the exogenous enzyme, single bacteria, bacteria and enzyme were added to the extract of sun dried green tea of Yunnan large leaf species.The specific research contents are as follows:(1)In order to study the acid protease, alkaline protease, neutral protease on Pu-erh tea quality influence, this paper they were added to the crude Pu-erh tea extract. Through observation of tea is turbid phenomenon and tea polyphenol content determination to determine the neutral protease is more suitable for in the tea extract. Neutral protease through the decomposition of protein increased the amino acid content at the same time improve the taste of tea fresh.(2)To detect the relationship between exogenous enzyme and fermentation of Pu-erh tea, temperature at 40℃, and last 4 hours were set as fixed factors. The single factor experiment was used to determine the optimal range of the action conditions using polyphenol oxidase, protease and tannin. Based on these conditions, complex orthogonal experiment was used to determine the most suitable amount of three enzymes: polyphenol oxidase 0.15%; protease 400 U/m L; tannin enzyme 0.03%. Under this condition, the content of tea polyphenols was 28.71%, the content of amino acid was 3.58%, the content of soluble sugar was 11.97%, and the content of theabrownin was 8.60%. This process has a significant effect on the promotion of tea polyphenol oxidation and the formation of tea brown pigment, and it can be used as a solid foundation for the study of rapid fermentation of Pu-erh tea.(3)This study with tea polyphenols, theabrownin and sensory evaluation as the evaluation criteria investigated effects of different fermentation modes on liquid fermentation of Pu-erh tea, first determine that the method of “The enzyme was added to the tea extract, and then the bacteria were added” is the most suitable for Pu-erh tea production process. The fermentation cycle is only 4 d, compared with the direct inoculation fermentation and pile fermentation, significantly shorten the fermentation period. In order to obtain the best effect of fermentation, the fermentation method was optimized by response surface method, Determine the best fermentation condition: the inoculation 1.1× 106个/ml, fermentation temperature 46℃, shaker speed of 147 r/ min, under this condition of experiment, theabrownin content reached 17.87%, close to the predicted value model is proved credible. |
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