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

Autori
Mihelj, Tea ; Belščak-Cvitanović, Ana ; Komes, Draženka ; Horžić, Dunja ; Tomašić, Vlasta

Izvornik
Journal of food and nutrition research (1336-8672) 53 (2014), 3; 278-290

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Yinzhen tea; ethanol; storage duration; polyphenols; methylxantines; HPLC-PDA

Sažetak
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).

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Prehrambena tehnologija

POVEZANOST RADA