title: LC-DAD-ESI-MS/MS characterization of phenolic constituents in Turkish black tea: Effect of infusion time and temperature.
abstract: The influence of different infusion times and temperatures on phenolic, antioxidant, and color properties of black teas (Camellia sinensis L.) was investigated in the present study. The teas were prepared using infusion times of 3, 6, and 10min at 80 and 100°C. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS), whereby the two purine alkaloids were detected using positive ESI, and the other 33 phenolic compounds were detected using negative ESI. A total of 35 phenolic compounds were identified and quantified in the tea infusions, with the most abundant being gallic acid, (-)-epicatechin-gallate, 4-p-coumaroylquinic acid, quercetin-3-O-galactosyl-rhamnosyl-glucoside, kaempferol-3-O-glucosyl-rhamnosyl-glucoside, theaflavin, and theobromine. The antioxidant capacity of the tea infusions was determined using two different methods: DPPH (2,2-diphenyl-1-picryl hydrazyl) and ABTS (2,2'-azino-bis-3-ethyl-benzothiazoline-6-sulfonic acid) assays. DPPH and the ABTS values varied largely among the tea preparations. The increment in infusion times and temperature led to increase in the tea's antioxidant capacities.
authors.affiliation: Adana Science and Technology University, Faculty of Engineering and Natural Sciences, Department of Food Engineering, 01180 Adana, Turkey. Electronic address: hkelebek@adanabtu.edu.tr.
authors.forename: Hasim
authors.initials: H
authors.lastname: Kelebek
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D052160:Benzothiazoles / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry; D028241:Camellia sinensis / Q000737:chemistry* / Q000254:growth & development; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D057230:Limit of Detection; D010636:Phenols / Q000032:analysis*; D010851:Picrates / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013451:Sulfonic Acids / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013662:Tea / Q000737:chemistry / Q000592:standards; D013696:Temperature; D014421:Turkey
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D013451:Sulfonic Acids; D013662:Tea; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: Antioxidant capacity; Camellia sinensis L.; LC–MS/MS; Phenolic compounds; Tea infusion