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Journal of Tea Science ›› 2006, Vol. 26 ›› Issue (2): 117-121.doi: 10.13305/j.cnki.jts.2006.02.008

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Research in Polyphenol Oxidase Activities of Major Oolong Tea Cultivars in Fujian

WANG Li-xia1, XIAO Li-xia2, *, LU Zheng3, LIN Qi-xun3, LU Ze-jian3   

  1. 1. Department of Biology, Zhangzhou Normal University, Zhangzhou 363000, China;
    2. College of Food Science and Engineering, Yangzhou University, Yangzhou 225009, Chian;
    3. College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
  • Received:2005-11-03 Revised:2006-03-02 Online:2006-06-25 Published:2019-09-10

Abstract: Crude polyphenol oxidase (PPO) was separately obtained from Maoxie, Tieguanyin, Huangdan, Rougui, and enzymatic properties were examined. The results were as follows: PPO activities increased curvely with the increase of catechol substrate volume if the volume of catechol substrate ranged in 0.3~0.9βml, and decreased when catechol substrate content was greater than 0.9βml, in the reaction system; the enzymatic activities were highest when the ratio of catechol substrate content to PPO content was 1.5:1, the optimum temperature for PPO activities were 45℃、55℃、65℃ respectively, under the condition of 50~90℃ hot water treatment for 1βh, the PPO activities of Maoxie, Tieguanyin, Huangdan, Rougui decreased 34.66%~55.91%, 22.68%~50.89%, 23.14%~53.57%, 31.58%~57.89% respectively, PPO could act under alkaline conditions, the best enzymatic activity was detected under the condition of pH8.6; All the five inhibitors showed some degree of inhibition to PPO activities and the most effective inhibitor was NaHSO3, next to which was L-cysteine, while the most ineffective inhibitor was NaCl.

Key words: Oolong tea, fresh tea, polyphenol oxidase

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