Bioactive compounds and antioxidant capacity of yellow Yinzhen tea affected by different extraction conditions

Mihelj, Tea; Belščak-Cvitanović, Ana; Komes, Draženka; Horžić, Dunja; Tomašić, Vlasta (2014) Bioactive compounds and antioxidant capacity of yellow Yinzhen tea affected by different extraction conditions. Journal of food and nutrition research, 53 (3). pp. 278-290. ISSN 1336-8672

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Abstract

Tea is one of the most popular beverages consumed worldwide. Polyphenols in tea contribute to its health benefits possessing high antioxidant, anticarcinogenic and antiallergic activity. The aim of this study was to examine the effect of ethanol concentration, tea forms and storage duration on polyphenols and methylxanthines composition, as well as antioxidant capacity of yellow Yinzhen tea. Total polyphenol, flavonoid concentration and antioxidant capacity were measured spectrofotometrically, while individual catechins and methylxanthines were identified and quantified using high performance liquid chromatography with photodiode array detector (HPLC-PDA). •DPPH (reduction of 1, 1-diphenyl-2-picrylhidrazyl), ABTS•+ (reaction of 2, 2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) and FRAP (reaction with iron(III)tripyridyltriazine) assays were applied to determine the antioxidant capacity. The highest polyphenol concentration and antioxidant capacity were determined in 75% ethanol tea extract stored for 24-hours. The application of lower ethanol concentration (50% or less) was the most efficient in individual catechins extraction. The most abundant catechin is epigallocatechin gallate, EGCG (12.60 ± 0.1 - 416.01 ± 2.70 mg•l-1), followed by the epigallocatechin, EGC (1.59 ± 0.10 - 264.92 ± 2.43 mg•l-1).

Item Type:	Article
Uncontrolled Keywords:	Yinzhen tea; ethanol; storage duration; polyphenols; methylxantines; HPLC-PDA
Subjects:	BIOTECHNICAL SCIENCES > Food Technology
Divisions:	Division of Physical Chemistry
Projects:	Project title Project leader Project code Project type Stability of alkaloids and polyphenols in food products of plant origin (Stabilnost alkaloida i polifenola u proizvodima biljnog podrijetla)- Draženka Komes 058-0000000-3470 MZOS
Depositing User:	Tea Mihelj
Date Deposited:	30 Nov 2015 14:41
URI:	http://fulir.irb.hr/id/eprint/2336

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