Determination of Total Aluminum, Chromium, Copper, Iron, Manganese, and Nickel and Their Fractions Leached to the Infusions of Black Tea, Green Tea, Hibiscus sabdariffa, and Ilex paraguariensis (Mate) by ETA-AAS

2000 ◽  
Vol 78 (1-3) ◽  
pp. 271-280 ◽  
Author(s):  
Katarzyna Wróbel ◽  
Kazimierz Wróbel ◽  
Edith Madaí Colunga Urbina
Keyword(s):  
Green Tea ◽  
Black Tea ◽  
Ilex Paraguariensis ◽  
Hibiscus Sabdariffa ◽  
Iron Manganese

Determination of flavonol glycosides in green tea, oolong tea and black tea by UHPLC compared to HPLC

2015 ◽  
Vol 183 ◽  
pp. 30-35 ◽  
Author(s):  
Heyuan Jiang ◽  
Ulrich H. Engelhardt ◽  
Claudia Thräne ◽  
Beate Maiwald ◽  
Janina Stark
Keyword(s):  
Green Tea ◽  
Black Tea ◽  
Flavonol Glycosides ◽  
Oolong Tea

scholarly journals Determination of Oxalate and Some Inorganic Anions in Green and Black Tea

2013 ◽  
Vol 67 (4-5) ◽  
pp. 429-432 ◽  
Author(s):  
Elena Yusenko ◽  
Evgeniya Polyntseva ◽  
Anna Lyzhova ◽  
Olga Kalyakina
Keyword(s):  
Oxalic Acid ◽  
Green Tea ◽  
Ion Chromatography ◽  
Black Tea ◽  
Inorganic Anions ◽  
Sample Treatment ◽  
Oxalate Concentration ◽  
Relative Standard ◽  
Oxalate Ions

Abstract Oxalate concentration differs in various daily consumed food products. The role of oxalic acid in the human body is very significant, as its compounds are responsible for the stability of biological membranes. However, insoluble calcium and magnesium oxalates can be accumulated in the body in the form of kidney stones. Oxalate concentration has been measured by high performance liquid, gas after derivatization and ion chromatography (IC). The most effective method for the simultaneous determination of oxalate and inorganic anions is ion chromatography with conductometric detection. Here, we report the results of the measurement of oxalic acid in bleak and green tea samples. Separation was performed by IC on an anion-exchange column Shodex IC SI-90 with surface-layer sorbent and conductimetric detection. The main analytical features of the method were: limit of detection of oxalic acid 0.03 mg/l, linear range 0.1-20 mg/l, correlation 0.9998, relative standard deviation 1%. The method did not need specific sample treatment and was successfully applied to the analysis of black and green tea samples. Oxalic acid was determined in the ranges 16.7-84 mg/l for green tea and 63-116 mg/l for black tea. Green tea contained lower oxalate ions concentration than black tea. The IC method has a lower detection limit for oxalate ions than HPLS and GC, ten and two times less, respectively

Determination of lemon and carbonate effects on caffeine content of various teas and investigation of daily caffeine intakes / Çeşitli çayların içerdikleri kafein miktarlarına limon ve karbonatın etkisi ve günlük alım miktarlarının incelenmesi

2016 ◽  
Vol 41 (5) ◽  
Author(s):  
Funda Demir ◽  
Azmi Seyhun Kıpçak ◽  
Özgül Dere Özdemir ◽  
Mehmet Burçin Pişkin ◽  
Emek Möröydor Derun
Keyword(s):  
Green Tea ◽  
Camellia Sinensis ◽  
Black Tea ◽  
Daily Maximum ◽  
Caffeine Content ◽  
Tea Infusions ◽  
Health Field

AbstractObjective: Tea (Camellia sinensis), has been used for health field in thousands of years. Caffeine is one of the key component in tea and investigation of caffeine is a popular working subject among the researches. The novelty of this study is not only the determination of the caffeine contents of the teas, but also how addition of lemon and carbonate effects the caffeine contents. Another aim of the study is the investigation of the daily caffeine intakes from teas.Methods: Tea infusions were prepared and caffeine contents were extracted by using chloroform and determined by UV-Vis Spectrophotometer. For lemon and carbonate addition experiments, lemon was added before the caffeine analysis and carbonate was added at the beginning.Results: Maximum caffeine contents from highest to lowest were seen in black, earl grey and green in classic teas; fennel, mint and sage in herbal teas; lemon, apple and rosehip in fruit teas. With lemon addition caffeine contents were increased except green tea and with carbonate addition caffeine contents were decreased except black and fennel tea. Daily caffeine intakes are found between 32.10% (green tea with carbonate) - 77.20% (black tea with lemon), 1.85% (sage tea with carbonate) - 4.05% (fennel tea with lemon) and 2.10% (rosehip with carbonate) - 4.00% (lemon tea with lemon) in classic, herbal and fruit teas, respectively.Conclusion: The significance of this study indicates that herbal and fruit teas contain caffeine, which is assumed zero in literature. The caffeine amount of herbal teas (20.79±0.36-30.68±0.63 ppm) were found barely higher than the fruit teas (22.87±0.54-28.54±0.75 ppm) but daily maximum caffeine intakes were found less than 5%. The daily maximum caffeine intakes were found in the teas as 525.36±2.84-20.79±0.36 ppm, where lemon addition increased to 617.90±3.54-22.97±0.58 ppm and carbonate addition decreased to 488.54±2.05-16.84±0.28 ppm.

scholarly journals CONCENTRAÇÃO DE CAFEÍNA EM Camellia sinensis

2018 ◽  
Vol 10 (3) ◽  
pp. 09-15
Author(s):  
Daniele Nascimento Silva ◽  
Marielle Flaviane de Carvalho Pimentel ◽  
Daniel Ângelo Macena ◽  
Vinícius Marques Gomes
Keyword(s):  
Green Tea ◽  
Camellia Sinensis ◽  
Black Tea ◽  
Ultraviolet Region ◽  
Physiological Effects ◽  
Chemical Dependence ◽  
White Tea ◽  
Low Concentrations ◽  
The World

Considering that tea is the second most consumed drink in the world it is important not to have excess caffeine in its composition since it causes some physiological effects to humanhealth such as diuretic and chemical dependence. The present project had as objective to compare the results obtained from the determination of caffeine in teas from the Camellia sinensis species with those found in the literature. For that, three samplesof white tea, three of green tea and three of black tea of the same brand were used. The analyzes were performed in triplicates and caffeine determined by spectrophotometry in the ultraviolet region. Black tea had the highest caffeine content (0.106 mg / g), white tea 0.082 mg / g and green tea the lowest (0.067 mg / g). However, the three types of teas have low concentrations when compared to the literature that presented values between 14.3 and 40.0 mg / g of caffeine of tea.

scholarly journals Analisis Kadar Kafein Dari Serbuk Teh Hitam, Teh Hijau dan Teh Putih (Camellia sinensis L.)

2016 ◽  
Vol 1 (1) ◽  
pp. 15-17
Author(s):  
Ratih Kusuma Wardani ◽  
M. A. Hanny Ferry Fernanda
Keyword(s):  
Green Tea ◽  
Black Tea ◽  
Liquid Extraction ◽  
The Body ◽  
Uv Spectrophotometry ◽  
White Tea ◽  
Caffeine Content ◽  
Brewing Time ◽  
Caffeine Level

ABSTRAKTeh diklasifikasikan menjadi 3 jenis yaitu teh hitam, teh hijau dan teh putih. Teh mengandung senyawa kafein yang dapat bermanfaat dan merugikan bagi tubuh. Senyawa kafein dalam teh dapat dipisahkan dengan metode ekstraksi cair-cair menggunakan kloroform dan penambahan CaCO3. Penentuan kadar kafein menggunakan metode spektrofotometri UV diukur pada panjang gelombang 275 nm. Kadar kafein dipengaruhi oleh suhu dan waktu penyeduhan. Semakin tinggi suhu dan lama waktu penyeduhan, kadar kafein dalam teh semakin meningkat. Kadar kafein dari berbagai jenis teh dari kadar yang tinggi ke rendah berturut-turut yaitu serbuk teh hitam, teh putih dan teh hijau dengan suhu penyeduhan 95ᵒC selama 10 menit.Kata Kunci: Teh hitam, teh hijau, teh putih, kafein, spektrofotometri UVABSTRACTTea is classified into three type, which are black tea, green tea and white tea. Tea contains caffeine compound that can be beneficial and harmful for the body. Caffeine compound in tea can be separated by liquid extraction method using chloroform and addition of CaCO3. The determination of the caffeine content measured by UV spectrophotometry at 275 nm. Caffeine level is influenced by temperature and brewing time. The highertemperature and the longer brewing time, the level of caffeine in tea increase. The caffeine content of various types of tea from high to low level respectively are black tea powder, white tea and green tea with temperature of 95ᵒC and 10 minutes brewing time.Keywords: Black tea, green tea, white tea, caffeine, UV spectrophotometry

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