Effect of Catechins Extract of Green Tea on Quality Protection of Black Tea-bag During Storage

ABSTRACT Here we provide a comprehensive meta-analysis to summarize and appraise the quality of the current evidence on the associations of tea drinking in relation to cancer risk. PubMed, Embase, and the Cochrane Database of Systematic Reviews were searched up to June 2020. We reanalyzed the individual prospective studies focused on associations between tea drinking and cancer risk in humans. We conducted a meta-analysis of prospective studies and provided the highest- versus lowest-category analyses, dose-response analyses, and test of nonlinearity of each association by modeling restricted cubic spline regression for each type of tea. We graded the evidence based on the summary effect size, its 95% confidence interval, 95% prediction interval, the extent of heterogeneity, evidence of small-study effects, and excess significance bias. We identified 113 individual studies investigating the associations between tea drinking and 26 cancer sites including 153,598 cancer cases. We assessed 12 associations for the intake of black tea with cancer risk and 26 associations each for the intake of green tea and total tea with cancer risk. Except for an association between lymphoid neoplasms with green tea, we did not find consistent associations for the highest versus lowest categories and dose-response analyses for any cancer. When grading current evidence for each association (number of studies ≥2), weak evidence was detected for lymphoid neoplasm (green tea), glioma (total tea, per 1 cup), bladder cancer (total tea, per 1 cup), and gastric and esophageal cancer (tea, per 1 cup). This review of prospective studies provides little evidence to support the hypothesis that tea drinking is associated with cancer risk. More well-designed studies are still needed to identify associations between tea intake and rare cancers.

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Tea Polyphenols in Promotion of Human Health

Nutrients ◽

10.3390/nu11010039 ◽

2018 ◽

Vol 11 (1) ◽

pp. 39 ◽

Cited By ~ 88

Author(s):

Naghma Khan ◽

Hasan Mukhtar

Keyword(s):

Green Tea ◽

Animal Studies ◽

Neurological Diseases ◽

Black Tea ◽

Polyphenolic Compounds ◽

Tea Polyphenols ◽

Beneficial Effects ◽

Gallocatechin Gallate ◽

Prevention Of Cancer ◽

Pharmacologically Active

Tea is the most widely used beverage worldwide. Japanese and Chinese people have been drinking tea for centuries and in Asia, it is the most consumed beverage besides water. It is a rich source of pharmacologically active molecules which have been implicated to provide diverse health benefits. The three major forms of tea are green, black and oolong tea based on the degree of fermentation. The composition of tea differs with the species, season, leaves, climate, and horticultural practices. Polyphenols are the major active compounds present in teas. The catechins are the major polyphenolic compounds in green tea, which include epigallocatechin-3-gallate (EGCG), epigallocatechin, epicatechin-3-gallate and epicatechin, gallocatechins and gallocatechin gallate. EGCG is the predominant and most studied catechin in green tea. There are numerous evidences from cell culture and animal studies that tea polyphenols have beneficial effects against several pathological diseases including cancer, diabetes and cardiovascular diseases. The polyphenolic compounds present in black tea include theaflavins and thearubigins. In this review article, we will summarize recent studies documenting the role of tea polyphenols in the prevention of cancer, diabetes, cardiovascular and neurological diseases.

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TLC analysis of some phenolic compounds in kombucha beverage

Acta periodica technologica ◽

10.2298/apt0435199m ◽

2004 ◽

pp. 199-205 ◽

Cited By ~ 3

Author(s):

Radomir Malbasa ◽

Eva Loncar ◽

Ljiljana Kolarov

Keyword(s):

Phenolic Compounds ◽

Thin Layer ◽

Thin Layer Chromatography ◽

Green Tea ◽

Black Tea ◽

Wide Range ◽

Tea Fungus ◽

Natural Phenolic Compounds ◽

Tlc Analysis ◽

Layer Chromatography

Black and green tea contains a wide range of natural phenolic compounds Flavanoids and their glycosides, catechins and the products of their condensation, and phenolic acids are the most important. Kombucha beverage is obtained by fermentation of tea fungus on black or green tea sweetened with sucrose. The aim of this paper was to investigate the composition of some phenolic compounds, catechin, epicatechin, quercetin, myricetin, gallic and tanic acid, and monitoring of their status during tea fungus fermentation. The method used for this study was thin layer chromatography with two different systems. The main phenolic compounds in the samples with green tea were catechin and epicatechin, and in the samples with black tea it was quercetin.

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Immobilization and Characterization of Tannase and its Haze-removing

Food Science and Technology International ◽

10.1177/1082013209352919 ◽

2009 ◽

Vol 15 (6) ◽

pp. 545-552 ◽

Cited By ~ 9

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.

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

Food Chemistry ◽

10.1016/j.foodchem.2015.03.024 ◽

2015 ◽

Vol 183 ◽

pp. 30-35 ◽

Cited By ~ 69

Author(s):

Heyuan Jiang ◽

Ulrich H. Engelhardt ◽

Claudia Thräne ◽

Beate Maiwald ◽

Janina Stark

Keyword(s):

Green Tea ◽

Black Tea ◽

Flavonol Glycosides ◽

Oolong Tea

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

Proceedings of the Latvian Academy of Sciences Section B Natural Exact and Applied Sciences ◽

10.2478/prolas-2013-0076 ◽

2013 ◽

Vol 67 (4-5) ◽

pp. 429-432 ◽

Cited By ~ 1

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

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

GSC Biological and Pharmaceutical Sciences ◽

10.30574/gscbps.2021.14.1.0416 ◽

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.

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