Chemical Forms of Iron, Calcium, Magnesium, Zinc, and Copper from Rats Diets Containing Tea

1988 ◽  
Vol 51 (9) ◽  
pp. 711-714 ◽  
Author(s):  
LAUREN S. JACKSON ◽  
KEN LEE
Keyword(s):  
Green Tea ◽  
Freeze Drying ◽  
Black Tea ◽  
Chemical Forms ◽  
Chemical Availability ◽  
Calcium Magnesium ◽  
Almost All ◽  
Low Solubility ◽  
Forms Of Iron

Chemical forms of iron, calcium, magnesium, zinc and copper were measured in rat diets containing 0–3.5% instant black tea. As instant tea in diets increased, more iron was soluble and ionic. Diets containing tea had more complexed iron than without. Calcium had low solubility (10–12%) while almost all magnesium (92–98%) was soluble in all diets. Solubility of zinc and copper increased as the level of tea in diets increased. Chemical availability of iron, calcium, magnesium and zinc was measured in a rat diet without tea (control), containing 2.31% black tea solids and containing 2.31% green tea solids. The control had more soluble (56%), ionic (37%) and complexed (19%) iron than green tea (18%, 2.3%, 16%, respectively) or black tea (8.7%, 4.8%, 3.9%, respectively) diets. Diets did not differ in calcium or magnesium solubility. Zinc was more soluble in both tea diets than the control. Some mineral profiles of the rat diets could be predicted by mineral profiles of teas alone. Changes in mineral profiles were induced by mixing tea with diet components or by freeze drying tea. Chemical availability of minerals in rat diets predicted some but not all results from a rat bioavailability assay.

Chemical Forms of Iron, Calcium, Magnesium and Zinc in Coffee and Rat Diets Containing Coffee

1988 ◽  
Vol 51 (11) ◽  
pp. 883-886 ◽  
Author(s):  
LAUREN S. JACKSON ◽  
KEN LEE
Keyword(s):  
Control Diet ◽  
Chemical Forms ◽  
Instant Coffee ◽  
Decaffeinated Coffee ◽  
Calcium Magnesium ◽  
Ionic Iron ◽  
Induced Changes ◽  
Low Solubility ◽  
Forms Of Iron ◽  
Soluble Complexes

Chemical forms of iron, calcium, magnesium and zinc (mineral profiles) were measured in brews of regular and decaffeinated instant coffee and diets containing these coffees. Iron, calcium and magnesium were highly soluble (90–98%) in brews of both coffees and zinc could not be detected. All ionic iron was in the ferric state and 40–48% of total iron was in soluble complexes. Iron was less soluble in a rat diet containing regular instant coffee (57%) and a diet containing decaffeinated coffee (62%) than in a control diet (74%). Diets had the same amounts of ferric and ionic iron (43–45%). More iron was in soluble complexes in control (29%) and decaffeinated coffee (21%) diets than a regular coffee diet (12%). Calcium had low solubility (12–14%) while magnesium had high solubility in diets. Zinc was more soluble in both coffee diets than in the control. Some mineral profiles of rat diets containing coffee were similar to mineral profiles of coffee alone. Differences indicated that mixing coffee into diets induced changes in coffee. Mineral profiles of diets predicted some results of a rat bioavailability assay.

Comparison of the Antioxidative Activities and Bioactive Compound Contents of Green Tea, Roasted Green Tea, and Black Tea

2018 ◽  
Vol 24 (3) ◽  
pp. 64-71 ◽  
Author(s):  
Eu-Jin Ban ◽  
Ju Hyung Kim ◽  
Gyu Yeon Oh ◽  
Su Yeon Lee ◽  
Jae-Hak Moon ◽  
...  
Keyword(s):  
Green Tea ◽  
Bioactive Compound ◽  
Black Tea

scholarly journals Tea Drinking and Risk of Cancer Incidence: A Meta-Analysis of Prospective Cohort Studies and Evidence Evaluation

2020 ◽  
Author(s):  
Long-Gang Zhao ◽  
Zhuo-Ying Li ◽  
Guo-Shan Feng ◽  
Xiao-Wei Ji ◽  
Yu-Ting Tan ◽  
...  
Keyword(s):  
Cancer Risk ◽  
Green Tea ◽  
Dose Response ◽  
Prospective Studies ◽  
Prediction Interval ◽  
Meta Analysis ◽  
Black Tea ◽  
Current Evidence ◽  
Tea Drinking ◽  
Risk Of Cancer

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.

scholarly journals Tea Polyphenols in Promotion of Human Health

Nutrients ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 39 ◽  
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.

scholarly journals TLC analysis of some phenolic compounds in kombucha beverage

2004 ◽  
pp. 199-205 ◽  
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.

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.

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