title: Enzymatic improvement in the polyphenol extractability and antioxidant activity of green tea extracts.
abstract: This study describes increases in extraction efficiency and the bioconversion of catechins after treatment with several commercial enzymes. Tannase was also used to improve the anti-radical activities of green tea extracts. Enzymatic treatment with various commercial enzymes was introduced to improve the extraction efficiency of polyphenols. The total polyphenol, flavonoid, and catechin contents and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of the green tea extract treated with Viscozyme (VG) were significantly higher than those treated with other commercial enzymatic extractions (p<0.05). More than 95% of the epigallocatechingallate (EGCG) and of the epicatechingallate (ECG) was hydrolyzed to epigallocatechin (EGC) and to epicatechin (EC) in successive 20 min treatments with Viscozyme and tannase (TG). Due to its hydrolytic activity, treatment involving tannase resulted in a significant release of gallic acid (GA), EGC, and EC, leading to greater radical scavenging activities. Regarding the IC(50) values of the DPPH and 2,2-azino-di-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, the green tea extract treated with TG showed values of 131.23 and 28.83 µg/mL, VG showed values of 224.70 and 32.54 µg/mL, and normal green tea extract (NG) showed values of 241.11 and 66.27 µg/mL, respectively. These results indicate that successive treatment with Viscozyme and tannase improves the extraction efficiency of polyphenols and increases radical scavenging activities.
authors.affiliation: Research Institute of Health and Sciences and Department of Food and Nutrition, Korea University, Seoul, Republic of Korea.
authors.forename: Yang-Hee
authors.initials: YH
authors.lastname: Hong
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Jung
authors.forename: Yooheon
authors.initials: Y
authors.lastname: Park
authors.forename: Kwang-Soon
authors.initials: KS
authors.lastname: Shin
authors.forename: Tae Young
authors.initials: TY
authors.lastname: Kim
authors.forename: Kwang-Won
authors.initials: KW
authors.lastname: Yu
authors.forename: Un Jae
authors.initials: UJ
authors.lastname: Chang
authors.forename: Hyung Joo
authors.initials: HJ
authors.lastname: Suh
mesh_terms: D000975:Antioxidants / Q000302:isolation & purification*; D052160:Benzothiazoles; D001713:Biphenyl Compounds / Q000037:antagonists & inhibitors; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives* / Q000302:isolation & purification*; D044602:Cellulases / Q000737:chemistry; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry; D005707:Gallic Acid / Q000302:isolation & purification*; D006026:Glycoside Hydrolases / Q000737:chemistry; D010851:Picrates / Q000037:antagonists & inhibitors; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D013451:Sulfonic Acids / Q000037:antagonists & inhibitors; D013662:Tea / Q000737:chemistry*; D013844:Thiazoles / Q000037:antagonists & inhibitors
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D005656:Fungal Proteins; D010851:Picrates; D010936:Plant Extracts; D013451:Sulfonic Acids; D013662:Tea; D013844:Thiazoles; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D005707:Gallic Acid; D002392:Catechin; C004931:1,1-diphenyl-2-picrylhydrazyl; D002265:Carboxylic Ester Hydrolases; C022711:tannase; D044602:Cellulases; D006026:Glycoside Hydrolases; C023305:hemicellulase; D043364:Endo-1,4-beta Xylanases; C057580:gallocatechol