Optimal reaction conditions and radical scavenging activities for the bioconversion of green tea using tannase

Yang Hee Hong, You Kyung Yeon, Eun Young Jung, Kwang Soon Shin, Kwang Won Yu, Tae Young Kim, Hyung Joo Suh

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


In this study, we optimized the reaction conditions for the bioconversion of green tea using tannase, and to evaluate its radical scavenging activities. Tea catechins such as (-)-epigallocatechin gallate (EGCG) or (-)-epicatechin gallate (ECG) were hydrolyzed by tannase to produce (-)-epigallocatechin (EGC) or (-)-epicatechin (EC), respectively, and a common product, gallic acid. The bioconversion of tea catechins by tannase was increased as enzyme concentration, substrate concentration and incubation time for enzyme dose. The results indicated the optimum reaction conditions for tannase were tannase 30 U/mL (enzyme concentration) on 1% green tea (substrate concentration) for 1 hr (incubation time for enzyme). Tannase enhanced the radical-scavenging properties of green tea; the 2,2-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging abilities were significantly (p<0.001) greater for the tannase-treated green tea extract compared to the untreated green tea extract. It is reported that ECG has the greatest antioxidant activity among the catechins in green tea, and the release of gallic acid is considered to be beneficial because of its significant antioxidant potency. The results of this study suggest that the tannase-treated green tea increases antioxidant activities under optimum reaction conditions.

Original languageEnglish
Pages (from-to)1501-1506
Number of pages6
JournalJournal of the Korean Society of Food Science and Nutrition
Issue number11
Publication statusPublished - 2011


  • Bioconversion
  • Catechins
  • Green tea
  • Radical scavenging activity
  • Tannase

ASJC Scopus subject areas

  • Food Science
  • Nutrition and Dietetics


Dive into the research topics of 'Optimal reaction conditions and radical scavenging activities for the bioconversion of green tea using tannase'. Together they form a unique fingerprint.

Cite this