scholarly journals Comparative study of catechin levels from green tea, oolong tea and black tea product with various treatments

2021 ◽  
Vol 14 (1) ◽  
pp. 001-010
Author(s):  
Syamsu Nur ◽  
Andi Nur Aisyah ◽  
Alfat Fadri ◽  
Sharfianty ◽  
Amriani Sapra ◽  
...  
Keyword(s):  
Green Tea ◽  
Color Change ◽  
Black Tea ◽  
Processing Method ◽  
Uv Spectrophotometry ◽  
Uv Spectrum ◽  
Polyphenol Compounds ◽  
The Public ◽  
Chemical Reagents ◽  
Oolong Tea

Background: Tea is a refreshing drink that contains polyphenol compounds, namely catechins that are used for medicine and cosmetics. This study was to assess the content of catechin compounds in green tea, oolong and black tea products from Indonesia, China and Taiwan. Methods: Some tea products are brewed at varying temperatures (75±2; 85±2 and 95±20 C) and times (5; 10 and 15 minutes). Identification of catechin compounds was carried out using chemical reagents and UV spectrophotometry. The level of cathecin in tea products were analyzed by spectrophotometer at 280 nm wavelength. Results: The results obtained indicate that green tea, oolong tea and black tea contain epigallocatechin-3-gallate (EGCG) compounds according to the color change based on chemical reagents and for UV spectrum analysis which has λmax in the range 268-274 nm. The results of quantitative tests using UV-Vis spectrophotometry showed that the green tea samples gave the highest levels of catechins followed by oolong tea and black tea with brewing temperature at 95±20 °C. Conclusion: The catechin content of tea obtained from various products varies according to the type of processing method and the brewing temperature. Therefore, this study is expected to provide information related to catechin content to the public and researchers.

Immobilization and Characterization of Tannase and its Haze-removing

2009 ◽  
Vol 15 (6) ◽  
pp. 545-552 ◽  
Author(s):  
Erzheng Su ◽  
Tao Xia ◽  
Liping Gao ◽  
Qianying Dai ◽  
Zhengzhu Zhang
Keyword(s):  
Kinetic Parameter ◽  
High Activity ◽  
Green Tea ◽  
Storage Stability ◽  
Residual Activity ◽  
Black Tea ◽  
Optimum Temperature ◽  
Oolong Tea ◽  
Optimum Ph

Tannase was effectively immobilized on alginate by the method of crosslinking-entrapment-crosslinking with a high activity recovery of 76.6%. The properties of immobilized tannase were investigated. Its optimum temperature was determined to be 35 ° C, decreasing 10 °C compared with that of free enzyme, whereas the optimum pH of 5.0 did not change. The thermal and pH stabilities of immobilized tannase increased to some degree. The kinetic parameter, Km, for immobilized tannase was estimated to be 11.6 × 10-4 mol/L. Fe2+ and Mn2+ could activate the activity of immobilized tannase. The immobilized tannase was also applied to treat the tea beverage to investigate its haze-removing effect. The content of non-estern catechins in green tea, black tea and oolong tea increased by 52.17%, 12.94% and 8.83%, respectively. The content of estern catechins in green tea, oolong tea and black tea decreased by 20.0%, 16.68% and 5.04%, respectively. The anti-sediment effect of green tea infusion treated with immobilized tannase was significantly increased. The storage stability and reusability of the immobilized tannase were improved greatly, with 72.5% activity retention after stored for 42 days and 86.9% residual activity after repeatedly used for 30 times.

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

Comparison of Antimutagenic Effect of Various Tea Extracts (Green, Oolong, Pouchong, and Black Tea)

1994 ◽  
Vol 57 (1) ◽  
pp. 54-58 ◽  
Author(s):  
GOW-CHIN YEN ◽  
HUI-YIN CHEN
Keyword(s):  
Salmonella Typhimurium ◽  
Green Tea ◽  
Aflatoxin B1 ◽  
Black Tea ◽  
Inhibitory Effect ◽  
Manufacturing Processes ◽  
Antimutagenic Effect ◽  
Oolong Tea ◽  
Tea Extract

The antimutagenic effects of various tea extracts prepared from nonfermented tea (green tea), semifermented tea (oolong tea and pouchong tea), and fermented tea (black tea) were investigated by Salmonella/microsome assay. No mutagenicity or toxicity in Salmonella typhimurium TA98 and TA100 was observed with any tea extract. The tea extracts markedly inhibited the mutagenicity of 2-amino-3-methylimidazo(4,5-f)quinoline, 3-amino-1,4-dimethyl-5H-pyridol(4,3-b)indole,2-amino-6-methyldipyrido(l,2-a:3′,2′-d)imidazole, benzo[a]pyrene, and aflatoxin B1 toward S. typhimurium TA98 and TA100 in the presence of S9 mixture, especially those of oolong and pouchong teas inhibited over 90% mutagenicity of these five mutagens at the dosage of 1 mg per plate. Among four tea extracts, black tea exhibited the weakest inhibitory effect on mutagenicity of these five mutagens. The mutagenicity of 4-nitroquinoline-N-oxide, a direct mutagen, was not inhibited by black and oolong tea extracts to S. typhimurium TA98 in the absence of S9 mixture but was increased by the tea extracts at the dose of 1 mg per plate to S. typhimurium TA100. As the antimutagenic effect of semifermented tea was stronger than nonfermented and fermented teas, some antimutagenic substances might be formed during manufacturing processes of tea.

scholarly journals Three different types of tea as surfactant in liquid exfoliation of graphite: green tea, black tea and oolong tea

2019 ◽  
Vol 702 ◽  
pp. 012036
Author(s):  
F S Ismail ◽  
K Yusoh ◽  
A S Zainal Abidin ◽  
A H Abdullah ◽  
Z Ismail
Keyword(s):  
Green Tea ◽  
Black Tea ◽  
Liquid Exfoliation ◽  
Oolong Tea ◽  
Different Types

The modulatory effect of infusions of green tea, oolong tea, and black tea on gut microbiota in high-fat-induced obese mice

2016 ◽  
Vol 7 (12) ◽  
pp. 4869-4879 ◽  
Author(s):  
Zhibin Liu ◽  
Zhichao Chen ◽  
Hongwen Guo ◽  
Dongping He ◽  
Huiru Zhao ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Green Tea ◽  
Black Tea ◽  
Tea Consumption ◽  
Obese Mice ◽  
High Fat ◽  
Oolong Tea

Tea consumption has been identified to have a gut microbiota modulatory effect, which may be related to its anti-obesity effect.

scholarly journals Perbandingan Total Mikroba Kombucha dengan Variasi Jenis Teh dan Lama Fermentasi

bionature ◽  
2020 ◽  
Vol 21 (2) ◽  
Author(s):  
Azrini Khaerah ◽  
Halijah Halijah ◽  
Nurhilmi Nawir
Keyword(s):  
Green Tea ◽  
Fermentation Process ◽  
Black Tea ◽  
Total Cell ◽  
White Tea ◽  
Oolong Tea ◽  
Fermented Beverage ◽  
Fermentation Period

Abstract. Kombucha is a fermented beverage made from tea and sugar. This fermentation is a work of bacteria and yeast consorsia that make a powerful symbiosis cooperation resulting kombucha with quality chemically increased. This kombucha is a healthful beverage for its consumer. Fermentation process can change the tea phisically, such as its taste, colour and flavor. During the fermentation period, the total cell of bacteria and yeast also change. In this research, kombucha is made from 4 different tea, such as black tea, green tea, oolong tea and white tea. As a result, found that the tea as a substrate and also the fermentation period affect the total of colony and cell of bacteria and yeast. In white tea and black tea kombucha perform decreased of total cell bacteria and yeast by the fermentation period, while in green tea and oolong tea kombucha increased. Keywords. kombucha, fermentation, total microbes, SCOBY, haemacytometer

Uji Aktivitas Antioksidan Teh Daun Sirsak (Annona Muricata Linn) Berdasarkan Teknik Pengolahan

2019 ◽  
Vol 4 (2) ◽  
pp. 84
Author(s):  
Mega Yulia ◽  
Riki Ranova
Keyword(s):  
Antioxidant Activity ◽  
Green Tea ◽  
Black Tea ◽  
Annona Muricata ◽  
Oolong Tea ◽  
Activity Test ◽  
The People ◽  
Expected Benefits ◽  
Tea Extract ◽  
Processing Techniques

<p><em>Teh merupakan salah satu minuman yang banyak dikonsumsi oleh masyarakat setelah air.   Berbagai macam jenis daun telah diolah menjadi teh oleh masyarakat seperti daun sirsak. Manfaat yang diharapkan dari mengkonsumsi teh daun sirsak adalah sebagai sumber antioksidan yang dapat menangkal berbagai jenis penyakit karena adanya kandungan acetogenin. Untuk menghasilkan teh yang bermutu tinggi, penanganan pucuk pasca panen perlu dilakukan dengan teknik sebaik mungkin. Penelitian ini bertujuan untuk mengetahui aktivitas antioksidan ekstrak teh daun sirsak berdasarkan variasi teknik pengolahan teh. Pengolahan dilakukan dengan 3 (tiga) variasi teknik pengolahan teh yaitu teh hijau, teh hitam dan teh oolong. Uji aktivitas antioksidan dilakukan dengan metoda penangkapan radikal bebas menggunakan DPPH (1,1-Difenil-2-pikrihidrazil).  Hasil penelitian menunjukan bahwa persentase inhibisi teh hijau sebesar 42,776%, teh oolong 39,962%, dan teh hitam 43,902%.  Aktivitas antioksidan tertinggi didapatkan pada pengolahan teh hitam daun sirsak.  Dari hasil penelitian dapat disimpulkan bahwa perbedaan teknik pengolahan teh tidak memberikan pengaruh terhadap aktivitas antioksidan.</em></p><p><em><br /></em></p><p><em><em>Tea is one drink that is widely consumed by people after water. Various types of leaves have been processed into tea by the people such as soursop leaves. The expected benefits of consuming soursop leaf tea is as a source of antioxidants that can ward off various types of diseases due to the presence of acetogenin. To produce high quality tea, handling after harvest needs to be done with the best possible technique. This study aims to determine the antioxidant activity of soursop leaf tea extract based on variations in tea processing techniques. Processing is done with 3 (three) variations of tea processing techniques, there are green tea, black tea and oolong tea. The antioxidant activity test was carried out by the method of capturing free radicals using DPPH (1,1-Diphenyl-2-pikrihidrazil). The results showed that the percentage of inhibition of green tea was 42.777%, oolong tea was 39.962%, and black tea was 43.902%. The highest antioxidant activity was found in the processing of soursop leaf is a black tea. From the results of this study can concluded there are differences in tea processing techniques do not affect the antioxidant activity</em></em></p>

Consumption of coffee, green tea, oolong tea, black tea, chocolate snacks and the caffeine content in relation to risk of diabetes in Japanese men and women

2009 ◽  
Vol 103 (3) ◽  
pp. 453-459 ◽  
Author(s):  
Shino Oba ◽  
Chisato Nagata ◽  
Kozue Nakamura ◽  
Kaori Fujii ◽  
Toshiaki Kawachi ◽  
...  
Keyword(s):  
Green Tea ◽  
Smoking Status ◽  
Menopausal Status ◽  
Coffee Consumption ◽  
Black Tea ◽  
Caffeine Intake ◽  
Inverse Association ◽  
Oolong Tea ◽  
Hazard Ratios ◽  
Study Participants

Although the inverse association between coffee consumption and risk of diabetes has been reported numerous times, the role of caffeine intake in this association has remained unclear. We evaluated the consumption of coffee and other beverages and food containing caffeine in relation to the incidence of diabetes. The study participants were 5897 men and 7643 women in a community-based cohort in Takayama, Japan. Consumption of coffee, green tea, oolong tea, black tea and chocolate snacks were measured with a semi-quantitative FFQ in 1992. At the follow-up survey in 2002, the development of diabetes and the time of diagnosis were reported. To assess the association, age, smoking status, BMI, physical activity, education in years, alcohol consumption, total energy intake, fat intake and women's menopausal status were adjusted. Among men who consumed one cup per month to six cups per week and among those who consumed one cup per d or more, the associated hazard ratios were 0·69 (95 % CI 0·50, 0·97) and 0·69 (95 % CI 0·49, 0·98) compared with those who drank little to no coffee, with a P value for trend of 0·32. The hazard ratios for women with the same coffee consumption patterns were 1·08 (95 % CI 0·74, 1·60) and 0·70 (95 % CI 0·44, 1·12), with a P value for trend of 0·03. The association between estimated total caffeine intake and risk of diabetes was insignificant both among men and among women. The results imply that coffee consumption decreased the risk of developing diabetes. The protective effect may exist aside from the influence of caffeine intake.

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