Theabrownins(TBs)are the characteristic functional and quality components of dark teas such as Pu’er tea and Chin-brick tea.TBs are a class of water-soluble brown polymers with multi-molecular weight distribution pro...Theabrownins(TBs)are the characteristic functional and quality components of dark teas such as Pu’er tea and Chin-brick tea.TBs are a class of water-soluble brown polymers with multi-molecular weight distribution produced by the oxidative polymerisation of tea polyphenols during the fermentation process of dark tea,both enzymatically and non-enzymatically.TBs have been extracted and purified from dark tea all the time,but the obtained TBs contain heterogeneous components such as polysaccharides and caffeine in the bound state,which are difficult to remove.The isolation and purification process was tedious and required the use of organic solvents,which made it difficult to industrialise TBs.In this study,epigallocatechin(EGC),epigallocatechin gallate(EGCG),epigallocatechin gallate(ECG),EGC/EGCG(mass ratio 1:1),EGCG/ECG(mass ratio 1:1),EGC/ECG(mass ratio 1:1)and EGC/EGCG/ECG(mass ratio 1:1:1)as substrates and catalyzed by polyphenol oxidase(PPO)and peroxidase(POD)in turn to produce TBs,named TBs-dE-1,TBs-dE-2,TBs-dE-3,TBs-dE-4,TBs-dE-5,TBs-dE-6 and TBs-dE-7.The physicochemical properties and the antibacterial activity and mechanism of TBs-dE-1–7 were investigated.Sensory and colour difference measurements showed that all seven tea browning samples showed varying degrees of brownish hue.Zeta potential in aqueous solutions at pH 3.0–9.0 indicated that TBs-dE-1–7 was negatively charged and the potential increased with increasing pH.The characteristic absorption peaks of TBs-dE-1–7 were observed at 208 and 274 nm by UV-visible(UV-vis)scanning spectroscopy.Fourier transform infrared(FT-IR)spectra indicated that they were phenolic compounds.TBs-dE-1–7 showed significant inhibition of Escherichia coli DH5α(E.coli DH5α).TBs-dE-3 showed the strongest inhibitory effect with minimum inhibitory concentration(MIC)of 1.25 mg mL–1 and MBC of 10 mg mL–1,followed by TBs-dE-5 and TBs-dE-6.These three TBs-dEs were selected to further investigate their inhibition mechanism.The TBs-dE was found to damage the extracellular membrane of E.coli DH5α,causing leakage of contents,and increase intracellular reactive oxygen content,resulting in abnormal cell metabolism due to oxidative stress.The results of the study provide a theoretical basis for the industrial preparation and product development of TBs.展开更多
[Objective] This study aimed to analyze the difference in the contents of gallic acid and catechins of tea resources from Yunnan Province. [Method] By using high performance liquid chromatography （HPLC）, the content...[Objective] This study aimed to analyze the difference in the contents of gallic acid and catechins of tea resources from Yunnan Province. [Method] By using high performance liquid chromatography （HPLC）, the contents of gallic acid （GA）, catechins （C）, epicatechin （EC）, epigallocatechin （EGC）, epicatechin gallate （ECG） and epigallocatechin gallate （EGCG） of 121 tea germplasms from the China National Germplasm Tea Repositories （CNGTR） at the Tea Research Institute of Yunnan Academy of Agricultural Sciences （TRIYAAS） were measured. [Result] The content of GA ranged from 0.210% to 1.902%, with an average of 0.834%, explaining rela- tively low GA content among tea germplasms. The content of C ranged from 0.069% to 8.865%, with an average of 1.916%. The content of EC ranged from 0.126% to 2.865%, with an average of 1.112%. The content of EGC ranged from 0.00% to 3.709%, with an average of 0.954%. The content of ECG ranged from 0.739% to 8.957%, with an average of 4.063%. The content of EGCG ranged from 0.819% to 11.77%, with an average of 5.939%. The content of total C ranged from 6.354% to 22.654%, with an average of 14.042%. [Conclusion] There was relatively big difference of catechin contents among different tea resources, indicating that there was plentiful biodiversity of Yunnan tea germplasms. At the same time, three tea germplasms with high epigallocatechin gallate content （≥10%） was selected preliminarily, which would provide important materials for breeding tea cultivars with high EGCG content in the future.展开更多
Objective:To identify the bioactive compounds in catechins isolation and its components from green tea GMB-4 clone.Methods:Green tea GMB-4 clones were extracted with distilled water at 90C.Samples were eluted into the...Objective:To identify the bioactive compounds in catechins isolation and its components from green tea GMB-4 clone.Methods:Green tea GMB-4 clones were extracted with distilled water at 90C.Samples were eluted into the column with 10%ethanol.Subsequently,the column was eluted with95%ethanol and evaporated separately.Green tea extract was identified by thin layer chromatography.Catechins were separated by the stationary phase in column chromatography using polyamide with 10%ethanol eluent and 95%ethanol.The results of isolations were analyzed by high performance liquid chromatographic(HPLC)and LCMS/MS.Analysis of catechins by HPLC was done by external standard.Results:Fraction from 10%ethanol showed that four major peaks at retention time of1.663,2.367,2.950 and 4.890,indicated the presence of four catechins components including catechin,epicatechins,gallocatechin and epigallocatechin.Whereas,fraction from 95%ethanol showed two main peaks at retention time of 5.167 and 9.82,which indicated the presence of epigallocatechin gallate(EGCG)and epicatechin gallate(ECG).EGCG(m/z 459),epigallocatechin(m/z 307),ECG(m/z 443),and epicatechin(m/z 291)were isolated and separated successfully using HPLC and LC-MS/MS.Conclusions:The HPLC and LC-MS/MS methods were successfully tuned for the qualitative analysis of green tea extract with EGCG and ECG.Four major catechins were separated and identified by LC-MS/MS,such as EGCG,epigallocatechin,ECG and epicatechin.The result of HPLC analysis showed that EGCG and ECG were main components from catechins isolation of green tea GMB-4 clone.展开更多
Tea is one of the most popular beverages, consumed by over two thirds of the world’s population; but the aluminum accumulation property of tea plant is becoming the focus of many researches because of aluminum’s kn...Tea is one of the most popular beverages, consumed by over two thirds of the world’s population; but the aluminum accumulation property of tea plant is becoming the focus of many researches because of aluminum’s known adverse effect on human health. Investigation of the interactions of catechins with Al3+ showed that during the interaction of catechins with Al3+, the UV-vis spectrum of catechins was changed. Absorption of EGCG at 274 nm decreased and increased at 322 nm; EC and C’s at 278 nm changed little. The ratio of Al3+ to EGCG was 1:1 in pH 5.0 buffer solution; in pH 6.2 buffer solution, the ratio in the Al-EGCG complex was 1:1. Interestingly, while the ratio reached to over 2, after the complex of Al-EGCG started polymerization, the ratio in the polymer was 2:1. In pH 6.2 buffer solution, the complex behavior of C with Al3+ was the same as that of EGCG, with a little difference for EC. When the ratio of Al3+ to EC was <1, the complex in ratio was 1:2, but, the complex polymerized when the ratio of Al3+ to EC was >1. It was found that the ratio of Al3+ to EC in the polymer was 1:1. Polymerization of Al-catechin complexes might reduce aluminum absorption in the intestine. Kow value was also employed to study the properties of aluminum species in tea infusion (at gastric and intestine pH condition) and the effect of catechins and tea polyphenols on Kow in buffer solution. Results showed that Kow value rose much higher at the intestine pH than at the gastric pH. Tea polyphenols and catechins could greatly reduce aluminum Kow value in acetic buffer, indicating that these compounds may reduce aluminum absorption during tea intake.展开更多
This study was carried out to characterize total residual catechins and their fractions, polyphenolic contents and antioxidant activities of black teas enriched with high levels of theaflavin-3,3’-digallate. The made...This study was carried out to characterize total residual catechins and their fractions, polyphenolic contents and antioxidant activities of black teas enriched with high levels of theaflavin-3,3’-digallate. The made teas were processed from eleven selected cultivars. A comparative study was carried out between the processed teas and those from commercially grown Kenyan cultivars in relation to the above chemical parameters. A correlation matrix analysis was also conducted to find out whether a relationship existed between the antioxidant activities and the said chemical parameters. The total residual catechins were found to range between 3.10% and 8.08%. The total polyphenol levels varied between 19.00% and 28.90%, while the antioxidant activities of the teas ranged from 82.70% to 91.70%. There was a significant p < 0.001 correlation between the antioxidant activity and total polyphenols (r = 0.8948). There was also a high correlation p < 0.001 between the antioxidant activity and total catechins (r = 0.8878). Out of the four catechin fractions, the antioxidant activity correlated most with EGCG (r = 0.8774). The total polyphenolic contents and antioxidant activities for most of the cultivars were comparable to those of the green tea reference standard. From the figures obtained, it can be concluded that the most of the newly developed black teas of the selected cultivars have higher quality and enhanced antioxidant activities and that they can be recommended for commercial production.展开更多
The over-activated microglial cells induce neuroinflammation which has the main role in neurological disorders.The over-activated microglia can disturb neuronal function by releasing inflammatory mediators leading to ...The over-activated microglial cells induce neuroinflammation which has the main role in neurological disorders.The over-activated microglia can disturb neuronal function by releasing inflammatory mediators leading to neuronal dysfunctions and death.Thus,inhibition of over-activated microglia may be an effective therapeutic approach for modulating neuroinflammation.Experimental studies have indicated anti-neuroinflammatory effects of flavonoids such as green tea catechins.The current research was aimed to review the effect of green tea catechins in inhibiting microglial cells,inflammatory cascades,and subsequent neurological diseases.展开更多
Inhibition of atherogenesis through inhibition of lipid metabolism has not been explored while other inhibitions through inflammation, endothelial dysfunction and free radicals have done. Inhibition of atherogenesis v...Inhibition of atherogenesis through inhibition of lipid metabolism has not been explored while other inhibitions through inflammation, endothelial dysfunction and free radicals have done. Inhibition of atherogenesis via inhibition of lipid metabolism can be done through the mechanism of Reverse Cholesterol Transport (RCT). Signaling pathways that play a role in this mechanism is LXR signaling. LXR activation by an LXR agonist led increasing cholesterol efflux. Catechins based on bioinformatics study showed as a potent candidate LXR agonists that can be used as an inhibitor of atherogenesis. This study aims to prove that the administration Catechins green tea Clone GMB4 can prevent atherosclerosis through increasing mechanism cholesterol efflux from macrophage by taking effect of ABCA1, ABCG1, SRB1 gene expression in cultured macrophages were exposed ox-LDL. Long-term goals of the outcome of the research are the use of Catechins Green Tea Clones GMB4 as an inhibitor of atherogenesis so that it can be used as a complementary therapy for the treatment of atherosclerosis and cardiovascular diseases. The research is divided into 5 groups, namely the culture of macrophages without exposed ox-LDL, culture exposed ox-LDL and groups of Catechins dose I, II, III. In vitro study showed that administration of Catechins increases mRNA of ABCA1, whereas mRNA ABCG1 and SRB1 decreased at all three doses given. The result of protein profilling was identified a protein with a molecular weight of 70 kDa by SDS-PGE with silver staining.展开更多
Antimicrobial activity is one of the well-known biological characteristics of catechins, the main extract of green tea leaves. It is thought that catechins intercalate into the bacterial cell membrane and damage the l...Antimicrobial activity is one of the well-known biological characteristics of catechins, the main extract of green tea leaves. It is thought that catechins intercalate into the bacterial cell membrane and damage the lipid bilayer. However, the association between catechins and lipopolysaccharides, which consist of an O side chain, core oligosaccharide, and lipid A, has not been previously investigated. In this study, we evaluated the catechin sensitivity of Salmonella enterica mutants that lack the O side chain and have core oligosaccharides of different lengths. These rough mutants were more sensitive to catechins than a bacterial strain with intact lipopolysaccharide. We conclude that the O side chain and core oligosaccharide play an important role in protecting Gram-negative bacteria against the antimicrobial activity of catechins.展开更多
Tea is the second most popular beverage worldwide after water.Green tea has the highest nutraceutical values with well-established general health benefits and wide safety margins.Natural polyphenols found in green tea...Tea is the second most popular beverage worldwide after water.Green tea has the highest nutraceutical values with well-established general health benefits and wide safety margins.Natural polyphenols found in green tea,including(+)-catechin(C),(-)-epicatechin(EC),(+)-gallocatechin(GC),(-)-epigallocatechin(EGC),(-)-epicatechin-3-gallate(ECG),(-)-gallocatechin-3-gallate(GCG)and(-)-epigallocatehin-3-gallate(EGCG).They have many potent biological properties and therapeutic effects in human health and diseases.These small molecules have high bioavailability and specific therapeutic potential in eye tissues.Recently some researchers studied the metabolomic responses to the green tea.In this talk,summary of these studies will be reviewed and its potential applications in the ocular research will be discussed.展开更多
Green tea catechins are classified as (-)-epi-forms (2R, 3R) or (-)-forms (2S, 3R) with respect to stereoisomerism. The (-)-forms (2S, 3R) in catechin preparations obtained from green tea amounts to approximately 10% ...Green tea catechins are classified as (-)-epi-forms (2R, 3R) or (-)-forms (2S, 3R) with respect to stereoisomerism. The (-)-forms (2S, 3R) in catechin preparations obtained from green tea amounts to approximately 10% of total catechins, whereas the other 90% are (-)-epiforms (2R, 3R). High temperature induces the conversion of (-)-epiforms (2R, 3R) to (-)-forms (2S, 3R). This study investigated the effect of catechin prepa-rations containing 10, 20 and 30% (-)-forms (2S, 3R) on the oxidative and hydrolytic stability of butter. For comparison, butter with δ-tocopherol and BHT and butter without stabilizer were analysed. Butter stability was examined under conditions of refrigeration (8 oC) and freezing (-22 oC) and at temperature of 50 oC and 100 oC. Catechin preparations were more efficient butter stabilizers than BHT and δ-tocopherol. Thermal modification of catechins that led to the genera-tion of 20% of (-) forms (2S, 3R) improved their antioxidative efficacy, but longer treatment lead- ing to the formation of 30% of (-) forms (2S, 3R) decreased their antioxidative activity. The hy-drolytic stability of butter, however, increased as the amount of (-) forms (2S, 3R) increased.展开更多
Catechins in green tea have various useful features including antioxidant activity and preventive effects on metabolic syndrome. Various beverages that are enriched with tea catechins are marketed as Foods for Specifi...Catechins in green tea have various useful features including antioxidant activity and preventive effects on metabolic syndrome. Various beverages that are enriched with tea catechins are marketed as Foods for Specified Health Uses (FOSHU) in Japan. However, recent reports have indicated that excessive consumption of green tea extracts as a dietary supplement are associated with adverse health effects such as liver disorders. Various catechins and caffeine are constituents of FOSHU tea-based beverages. The amount of catechins in FOSHU products is displayed on labels as total catechin content, but the content of individual catechins are not provided. Although health hazards of FOSHU products have rarely been reported, precise information about the content and types of catechins in FOSHU products is needed to ensure safety. We used high-performance liquid chromatography with a photodiode array (HPLC/PDA) to simultaneously identify and quantify catechins and caffeine in green tea-based popular beverages and FOSHU beverages. This technique allowed simultaneous quantitation of five types of catechins and caffeine in green tea without complicated sample preparation. Epigallocatechin gallate (EGCG) and epigallocatechin EGC were the main catechins in various FOSHU beverages and the concentrations of almost all catechins were higher in FOSHU, than in popular green tea-based beverages. The concentrations of EGCG in green tea-based popular beverages and in FOSHU beverages were 5.4 - 7.3 and 10.2 - 41.9 mg/100mL, respectively, with the highest concentration being in a product named Healthya (approximately 147 mg/bottle). The simultaneous determination of compounds such as catechins and caffeine in FOSHU beverages can help to estimate beneficial and adverse effects to prevent deleterious effects on health and the excessive consumption of FOSHU beverages containing high concentrations of tea catechins should be avoided.展开更多
Background: The diversified and high value-added utilization of cotton by products can promote the sustainable development of modern agriculture. Di erences in potential nutrients among varieties can be explained by v...Background: The diversified and high value-added utilization of cotton by products can promote the sustainable development of modern agriculture. Di erences in potential nutrients among varieties can be explained by variations in the composition and abundance of fatty acids, polyphenols, carbohydrates, amino acids, and organic acids. Therefore, the analysis of metabolite species and relationships in cottonseed is meaningful for the development of cotton byproducts.Results: In this study, the metabolomes of three representative cotton cultivars of di erent species were compared using untargeted GC-TOF/MS analysis. A total of 263 metabolites were identified from 705 peaks, and their levels were compared across cultivars. Principal component analysis and OPLS-DA clearly distinguish these samples based on metabolites. There were significant di erences in the contents of amino acids, carbohydrates, organic acids, flavonoids, and lipids in G. hirsutum TM-1 compared with G. arboreum Shixiya1 and G. barbadense Hai7124. Notably, the bioactive nutrient compound catechin obtained from the di erential metabolites significantly accumulated in TM-1. Furthermore, a comprehensive analysis using catechin and oil-related traits was conducted in core collections of Gossypium hirsutum. The results revealed the reliability of the GC-TOF/MS analysis, as well as that catechin content has a negative association with myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, and total fatty acids.Conclusion: These findings suggest that untargeted GC-TOF/MS analysis could provide a new method for investigating the underlying plant biochemistry of nutrient variation in cottonseed, and that catechin content has a negative association with oil-related traits in cottonseed. This study may pave the way to exploit the value of cotton byproducts.展开更多
A series of extractants （tert-butylcalix[6]arene, tert-butylcalix[8]arene and octeacetate of tert-butylcalix[8]arene） were synthesized, and their structures were identified by IR and JH-NMR. The distribution behavio...A series of extractants （tert-butylcalix[6]arene, tert-butylcalix[8]arene and octeacetate of tert-butylcalix[8]arene） were synthesized, and their structures were identified by IR and JH-NMR. The distribution behavior of ester catechins monomer in the aqueous and chloroform two-phase system containing one of calixarene was studied. The influences of different extractants, concentration of tert-butylcalix[8]arene and extraction temperature on the partition coefficients and the separation factors were investigated. The experiment results show that tert-butylcalix[8]arene is the best extractant that forms a more stable supramolecular compound with gallocatechin gallate （GCG） than with epigallocathechin gallate （EGCG） or epicatechin gallate （ECG）. When the concentration ofp-tert-butylcalix[8]arene is 3.79 mmol/L, the extraction temperature is 4 ℃, the partition coefficients ofKGCG, KECG, KEGCG are 0.987, 0.629, 0.449, the separation factors of al and a2 are 1.450 and 1.596, respectively. The important factors influencing the extraction properties of calixarene are discovered to be its cavity size and hydrogen bonding.展开更多
Objective:To discuss the effect of catechins on myocardial injury and inflammatory factors in rats with coronary heart disease under PI3K/Akt/eNOS signaling pathway.Methods:A total of 50 healthy adult pathogen-free(SP...Objective:To discuss the effect of catechins on myocardial injury and inflammatory factors in rats with coronary heart disease under PI3K/Akt/eNOS signaling pathway.Methods:A total of 50 healthy adult pathogen-free(SPF)-grade SD rats were divided into five groups by random number table method.Except for the blank group,the other four groups were fed with high fat to construct a rat model of coronary artery disease.After the model was successfully constructed,the blank group and the model group were given saline by gavage,the positive group was given 25 mg/kg aspirin by gavage,the low-dose group was given 20 mg/kg catechin by gavage,and the high-dose group was given 60 mg/kg catechin by gavage.The expression levels of PI3K/Akt/eNOS signaling pathway-related proteins,myocardial injury markers,myocardial infarction and myocardial inflammatory factors were observed and compared in the five groups.Results:Overall,there were significant differences in the expression levels of PI3K,p-Akt/Akt,and p-eNOS/eNOS in the five groups of rats(P<0.05);there were significant differences in the expression levels of CK-MB and c Tn I in the five groups of rats(P<0.05);there were significant differences in ischemic area,infarct area,and myocardial infarction range in the four groups of rats,except for the blank group(P<0.05);there were significant differences in the expression levels of IL-1β,IL-18,TNF-α,and ET-1 in the five groups of rats(P<0.05).Conclusion:Catechins can reduce the severity of myocardial injury,reduce the range of myocardial infarction,and reduce myocardial inflammation in rats with coronary heart disease by up-regulating expression level of PI3K/Akt/eNOS signaling pathway-related proteins.Compared with aspirin,high-dose catechins have a more prominent protective effect on the myocardium of rats with coronary heart disease.展开更多
Epidemiological evidence and experimental studies suggest that drinking green tea is associated with a lower risk of obesity and related diseases. However, the mechanisms of these effects are not clear. In the present...Epidemiological evidence and experimental studies suggest that drinking green tea is associated with a lower risk of obesity and related diseases. However, the mechanisms of these effects are not clear. In the present study, we investigated the anti-obesity mechanisms of green tea catechins (GTCs) through modulation of peroxisome proliferator activated-receptor (PPAR) pathways in high-fat diet-induced obesity in rats. GTC supplementation significantly attenuated the increased body and liver weights and the elevated serum and liver triglyceride levels. Meanwhile, GTCs increased the PPARγ levels in subcutaneous white adipose tissue (SWAT) and decreased the PPAR levels in visceral white adipose tissue (VWAT). In addition, GTC treatment up-regulated the levels of PPARδ in SWAT, VWAT, and brown adipose tissue and increased the expression of genes involved in fatty acid oxidation in brown adipose tissue. Our results suggest that GTCs exert their anti-obesity mechanism in part by modulating PPAR signaling pathways.展开更多
This study was conducted to investigate the effects of catechins on reproductive performance, antioxidative capacity and immune function of gestating sows. A total of 60 cross-bred（Landrace × Large White） multi...This study was conducted to investigate the effects of catechins on reproductive performance, antioxidative capacity and immune function of gestating sows. A total of 60 cross-bred（Landrace × Large White） multiparious sows were blocked by body weight, parity and backfact and randomly allocated to 1 of 5 treatments: 0.100,200,300, or 400 mg/kg catechins. Dietary treatments were imposed from mating to d 40 of gestation of sows. At farrowing, litter total born, born alive, dead, and normal-（healthy piglets,>0.85 kg） and low-birth weight piglets（<0.85 kg） were recorded. Within 3.00 ± 0.50 days after farrowing litter size was standardized to 8,00 ± 1.50 piglets within treatment. The piglets were weighed at birth（d 1） and weaning（d 28）. Sows serum samples were obtained from blood samples collected on d 40 of gestation for analyses of glutathione peroxidase（GSH-Px）, superoxide dismutase（SOD）, catalase（CAT）,malondialdehyde（MDA）, hydrogen peroxide（H2 O2）, nitric oxide synthetase（NOS） and nitrogen monoxide（NO）. Our results showed that supplementation of catechins at levels of 200 or 300 mg/kg led to improvements in litter born alive（P < 0.01） and piglet born healthy（P < 0.01） and a decrease in stillborn（P < 0.05） at farrowing when compared with the control. In comparison with the control, catechins at any supplemental levels all enhanced the serum SOD（P < 0.05） and CAT（P < 0.01） activities of sows at farrowing but no obvious differences in the serum GSH-Px and NOS activities were observed in this trial（P > 0.05）. Sows received 200 mg catechin per kg diets showed a reduction（P < 0.05） of the serum MDA level at farrowing compared with all other treatments. Sows received all the levels of catechin showed a reduction（P < 0.05） of serum H2 O2 level compared with sows received the control diet on both d 40 of gestation and farrowing. Our results demonstrated that the catechins may be a potential antioxidant to increase the reproductive performance and antioxidative capacity of sows when it was added into diets during the early gestation.展开更多
The catechin Epigallocatechin-3-O-Gallate (EGCG) which is found in of Green Tea extracts (GTE), displays a variety of microbicidal properties. It is largely believed that EGCG inhibits the growth of cariogenic and per...The catechin Epigallocatechin-3-O-Gallate (EGCG) which is found in of Green Tea extracts (GTE), displays a variety of microbicidal properties. It is largely believed that EGCG inhibits the growth of cariogenic and periodontopathic bacteria. Objective: In this paper we compared the inhibitory activity of EGCG and a commercial GTE on the growth of Veillonella parvula. Chlorhexidine was used as positive control. Methodology: V. parvula ATCC 10790 and a clinical isolate obtained from a periodontal disease patient were cultured in the presence of EGCG or a commercial GTE, and the measurements of bacterial growth inhibition were compared to the values obtained with 0.12 and 0.2% chlorhexidine. Results: Chlorhexidine inhibited bacterial growth, however in contrast to a previous report, neither EGCG nor the GTE showed any effect on bacterial growth. Conclusions: The data show and confirm that chlorhexidine is a growth inhibitor of V. parvula while EGCG and GTE do not display such effect.展开更多
The intensity of the bitterness of catechins increases with increased concentration, but the taste palatability decreased in green tea extract. The aim of this study was to investigate whether a blend of tea leaf part...The intensity of the bitterness of catechins increases with increased concentration, but the taste palatability decreased in green tea extract. The aim of this study was to investigate whether a blend of tea leaf particles of various sizes would result in a good balance between catechin content and appreciable taste. The control is common tea (CT) with 6 - 10 mm long leaves. Blend tea (BT) was prepared by mixing 5 mm and 120 - 130 mm long tea leaves in a ratio of 3:2. The catechin content of hot water extracts was analyzed by HPLC, and the sensory test was conducted with 99 volunteers. In BT, the total catechin content was significantly higher than that in CT. The sensory test results revealed that BT was less bitter and had more preferable color than CT. More catechins were extracted from BT, but it tasted less bitter. Thus, the recalibration of the tea leaf particle size can result in good balance between catechin content and palatability.展开更多
Bitter tea is a special kind of tea germplasm in China.The major biochemical components of 24 bitter teas and other 8 Camellia sinensis var.sinensis and 8 C.sinensis var.assamica tea germplasms,which were stored in th...Bitter tea is a special kind of tea germplasm in China.The major biochemical components of 24 bitter teas and other 8 Camellia sinensis var.sinensis and 8 C.sinensis var.assamica tea germplasms,which were stored in the China National Germplasm Hangzhou Tea Repository(CNGHTR),were analyzed and evaluated.The results showed that no significant differences of major biochemical components affecting the tea quality were found between bitter tea and common tea.According to the processing suitability index,bitter tea was suitable for the manufacturing of black tea;while according to evolutionary indices such as the composition and content of catechin,bitter tea was similar to C.sinensis var.assamica belonging to the relatively primitive type in evolution.The results of cluster analysis indicated that bitter tea was clustered with C.sinensis var.assamica,so it could be considered to belong to C.sinensis var.assamica.展开更多
基金financially supported by the National Natural Science Foundation of China(31871813).
文摘Theabrownins(TBs)are the characteristic functional and quality components of dark teas such as Pu’er tea and Chin-brick tea.TBs are a class of water-soluble brown polymers with multi-molecular weight distribution produced by the oxidative polymerisation of tea polyphenols during the fermentation process of dark tea,both enzymatically and non-enzymatically.TBs have been extracted and purified from dark tea all the time,but the obtained TBs contain heterogeneous components such as polysaccharides and caffeine in the bound state,which are difficult to remove.The isolation and purification process was tedious and required the use of organic solvents,which made it difficult to industrialise TBs.In this study,epigallocatechin(EGC),epigallocatechin gallate(EGCG),epigallocatechin gallate(ECG),EGC/EGCG(mass ratio 1:1),EGCG/ECG(mass ratio 1:1),EGC/ECG(mass ratio 1:1)and EGC/EGCG/ECG(mass ratio 1:1:1)as substrates and catalyzed by polyphenol oxidase(PPO)and peroxidase(POD)in turn to produce TBs,named TBs-dE-1,TBs-dE-2,TBs-dE-3,TBs-dE-4,TBs-dE-5,TBs-dE-6 and TBs-dE-7.The physicochemical properties and the antibacterial activity and mechanism of TBs-dE-1–7 were investigated.Sensory and colour difference measurements showed that all seven tea browning samples showed varying degrees of brownish hue.Zeta potential in aqueous solutions at pH 3.0–9.0 indicated that TBs-dE-1–7 was negatively charged and the potential increased with increasing pH.The characteristic absorption peaks of TBs-dE-1–7 were observed at 208 and 274 nm by UV-visible(UV-vis)scanning spectroscopy.Fourier transform infrared(FT-IR)spectra indicated that they were phenolic compounds.TBs-dE-1–7 showed significant inhibition of Escherichia coli DH5α(E.coli DH5α).TBs-dE-3 showed the strongest inhibitory effect with minimum inhibitory concentration(MIC)of 1.25 mg mL–1 and MBC of 10 mg mL–1,followed by TBs-dE-5 and TBs-dE-6.These three TBs-dEs were selected to further investigate their inhibition mechanism.The TBs-dE was found to damage the extracellular membrane of E.coli DH5α,causing leakage of contents,and increase intracellular reactive oxygen content,resulting in abnormal cell metabolism due to oxidative stress.The results of the study provide a theoretical basis for the industrial preparation and product development of TBs.
基金Supported by National Natural Science Foundation of China(31160175)Technology Innovation Talents Project of Yunnan Province(2011CI068)+1 种基金Special Fund for National Modern Agricultural Industrial Technology System Construction(nycytx-23)Seed Preservation Project of Ministry of Agriculture(NB2012-2130135)~~
文摘[Objective] This study aimed to analyze the difference in the contents of gallic acid and catechins of tea resources from Yunnan Province. [Method] By using high performance liquid chromatography （HPLC）, the contents of gallic acid （GA）, catechins （C）, epicatechin （EC）, epigallocatechin （EGC）, epicatechin gallate （ECG） and epigallocatechin gallate （EGCG） of 121 tea germplasms from the China National Germplasm Tea Repositories （CNGTR） at the Tea Research Institute of Yunnan Academy of Agricultural Sciences （TRIYAAS） were measured. [Result] The content of GA ranged from 0.210% to 1.902%, with an average of 0.834%, explaining rela- tively low GA content among tea germplasms. The content of C ranged from 0.069% to 8.865%, with an average of 1.916%. The content of EC ranged from 0.126% to 2.865%, with an average of 1.112%. The content of EGC ranged from 0.00% to 3.709%, with an average of 0.954%. The content of ECG ranged from 0.739% to 8.957%, with an average of 4.063%. The content of EGCG ranged from 0.819% to 11.77%, with an average of 5.939%. The content of total C ranged from 6.354% to 22.654%, with an average of 14.042%. [Conclusion] There was relatively big difference of catechin contents among different tea resources, indicating that there was plentiful biodiversity of Yunnan tea germplasms. At the same time, three tea germplasms with high epigallocatechin gallate content （≥10%） was selected preliminarily, which would provide important materials for breeding tea cultivars with high EGCG content in the future.
基金supported by a grant of Directorate of General Higher Education,Ministry of Education and Culture of Indonesia for the"BPPDN"scholarship
文摘Objective:To identify the bioactive compounds in catechins isolation and its components from green tea GMB-4 clone.Methods:Green tea GMB-4 clones were extracted with distilled water at 90C.Samples were eluted into the column with 10%ethanol.Subsequently,the column was eluted with95%ethanol and evaporated separately.Green tea extract was identified by thin layer chromatography.Catechins were separated by the stationary phase in column chromatography using polyamide with 10%ethanol eluent and 95%ethanol.The results of isolations were analyzed by high performance liquid chromatographic(HPLC)and LCMS/MS.Analysis of catechins by HPLC was done by external standard.Results:Fraction from 10%ethanol showed that four major peaks at retention time of1.663,2.367,2.950 and 4.890,indicated the presence of four catechins components including catechin,epicatechins,gallocatechin and epigallocatechin.Whereas,fraction from 95%ethanol showed two main peaks at retention time of 5.167 and 9.82,which indicated the presence of epigallocatechin gallate(EGCG)and epicatechin gallate(ECG).EGCG(m/z 459),epigallocatechin(m/z 307),ECG(m/z 443),and epicatechin(m/z 291)were isolated and separated successfully using HPLC and LC-MS/MS.Conclusions:The HPLC and LC-MS/MS methods were successfully tuned for the qualitative analysis of green tea extract with EGCG and ECG.Four major catechins were separated and identified by LC-MS/MS,such as EGCG,epigallocatechin,ECG and epicatechin.The result of HPLC analysis showed that EGCG and ECG were main components from catechins isolation of green tea GMB-4 clone.
文摘Tea is one of the most popular beverages, consumed by over two thirds of the world’s population; but the aluminum accumulation property of tea plant is becoming the focus of many researches because of aluminum’s known adverse effect on human health. Investigation of the interactions of catechins with Al3+ showed that during the interaction of catechins with Al3+, the UV-vis spectrum of catechins was changed. Absorption of EGCG at 274 nm decreased and increased at 322 nm; EC and C’s at 278 nm changed little. The ratio of Al3+ to EGCG was 1:1 in pH 5.0 buffer solution; in pH 6.2 buffer solution, the ratio in the Al-EGCG complex was 1:1. Interestingly, while the ratio reached to over 2, after the complex of Al-EGCG started polymerization, the ratio in the polymer was 2:1. In pH 6.2 buffer solution, the complex behavior of C with Al3+ was the same as that of EGCG, with a little difference for EC. When the ratio of Al3+ to EC was <1, the complex in ratio was 1:2, but, the complex polymerized when the ratio of Al3+ to EC was >1. It was found that the ratio of Al3+ to EC in the polymer was 1:1. Polymerization of Al-catechin complexes might reduce aluminum absorption in the intestine. Kow value was also employed to study the properties of aluminum species in tea infusion (at gastric and intestine pH condition) and the effect of catechins and tea polyphenols on Kow in buffer solution. Results showed that Kow value rose much higher at the intestine pH than at the gastric pH. Tea polyphenols and catechins could greatly reduce aluminum Kow value in acetic buffer, indicating that these compounds may reduce aluminum absorption during tea intake.
文摘This study was carried out to characterize total residual catechins and their fractions, polyphenolic contents and antioxidant activities of black teas enriched with high levels of theaflavin-3,3’-digallate. The made teas were processed from eleven selected cultivars. A comparative study was carried out between the processed teas and those from commercially grown Kenyan cultivars in relation to the above chemical parameters. A correlation matrix analysis was also conducted to find out whether a relationship existed between the antioxidant activities and the said chemical parameters. The total residual catechins were found to range between 3.10% and 8.08%. The total polyphenol levels varied between 19.00% and 28.90%, while the antioxidant activities of the teas ranged from 82.70% to 91.70%. There was a significant p < 0.001 correlation between the antioxidant activity and total polyphenols (r = 0.8948). There was also a high correlation p < 0.001 between the antioxidant activity and total catechins (r = 0.8878). Out of the four catechin fractions, the antioxidant activity correlated most with EGCG (r = 0.8774). The total polyphenolic contents and antioxidant activities for most of the cultivars were comparable to those of the green tea reference standard. From the figures obtained, it can be concluded that the most of the newly developed black teas of the selected cultivars have higher quality and enhanced antioxidant activities and that they can be recommended for commercial production.
文摘The over-activated microglial cells induce neuroinflammation which has the main role in neurological disorders.The over-activated microglia can disturb neuronal function by releasing inflammatory mediators leading to neuronal dysfunctions and death.Thus,inhibition of over-activated microglia may be an effective therapeutic approach for modulating neuroinflammation.Experimental studies have indicated anti-neuroinflammatory effects of flavonoids such as green tea catechins.The current research was aimed to review the effect of green tea catechins in inhibiting microglial cells,inflammatory cascades,and subsequent neurological diseases.
文摘Inhibition of atherogenesis through inhibition of lipid metabolism has not been explored while other inhibitions through inflammation, endothelial dysfunction and free radicals have done. Inhibition of atherogenesis via inhibition of lipid metabolism can be done through the mechanism of Reverse Cholesterol Transport (RCT). Signaling pathways that play a role in this mechanism is LXR signaling. LXR activation by an LXR agonist led increasing cholesterol efflux. Catechins based on bioinformatics study showed as a potent candidate LXR agonists that can be used as an inhibitor of atherogenesis. This study aims to prove that the administration Catechins green tea Clone GMB4 can prevent atherosclerosis through increasing mechanism cholesterol efflux from macrophage by taking effect of ABCA1, ABCG1, SRB1 gene expression in cultured macrophages were exposed ox-LDL. Long-term goals of the outcome of the research are the use of Catechins Green Tea Clones GMB4 as an inhibitor of atherogenesis so that it can be used as a complementary therapy for the treatment of atherosclerosis and cardiovascular diseases. The research is divided into 5 groups, namely the culture of macrophages without exposed ox-LDL, culture exposed ox-LDL and groups of Catechins dose I, II, III. In vitro study showed that administration of Catechins increases mRNA of ABCA1, whereas mRNA ABCG1 and SRB1 decreased at all three doses given. The result of protein profilling was identified a protein with a molecular weight of 70 kDa by SDS-PGE with silver staining.
文摘Antimicrobial activity is one of the well-known biological characteristics of catechins, the main extract of green tea leaves. It is thought that catechins intercalate into the bacterial cell membrane and damage the lipid bilayer. However, the association between catechins and lipopolysaccharides, which consist of an O side chain, core oligosaccharide, and lipid A, has not been previously investigated. In this study, we evaluated the catechin sensitivity of Salmonella enterica mutants that lack the O side chain and have core oligosaccharides of different lengths. These rough mutants were more sensitive to catechins than a bacterial strain with intact lipopolysaccharide. We conclude that the O side chain and core oligosaccharide play an important role in protecting Gram-negative bacteria against the antimicrobial activity of catechins.
文摘Tea is the second most popular beverage worldwide after water.Green tea has the highest nutraceutical values with well-established general health benefits and wide safety margins.Natural polyphenols found in green tea,including(+)-catechin(C),(-)-epicatechin(EC),(+)-gallocatechin(GC),(-)-epigallocatechin(EGC),(-)-epicatechin-3-gallate(ECG),(-)-gallocatechin-3-gallate(GCG)and(-)-epigallocatehin-3-gallate(EGCG).They have many potent biological properties and therapeutic effects in human health and diseases.These small molecules have high bioavailability and specific therapeutic potential in eye tissues.Recently some researchers studied the metabolomic responses to the green tea.In this talk,summary of these studies will be reviewed and its potential applications in the ocular research will be discussed.
文摘Green tea catechins are classified as (-)-epi-forms (2R, 3R) or (-)-forms (2S, 3R) with respect to stereoisomerism. The (-)-forms (2S, 3R) in catechin preparations obtained from green tea amounts to approximately 10% of total catechins, whereas the other 90% are (-)-epiforms (2R, 3R). High temperature induces the conversion of (-)-epiforms (2R, 3R) to (-)-forms (2S, 3R). This study investigated the effect of catechin prepa-rations containing 10, 20 and 30% (-)-forms (2S, 3R) on the oxidative and hydrolytic stability of butter. For comparison, butter with δ-tocopherol and BHT and butter without stabilizer were analysed. Butter stability was examined under conditions of refrigeration (8 oC) and freezing (-22 oC) and at temperature of 50 oC and 100 oC. Catechin preparations were more efficient butter stabilizers than BHT and δ-tocopherol. Thermal modification of catechins that led to the genera-tion of 20% of (-) forms (2S, 3R) improved their antioxidative efficacy, but longer treatment lead- ing to the formation of 30% of (-) forms (2S, 3R) decreased their antioxidative activity. The hy-drolytic stability of butter, however, increased as the amount of (-) forms (2S, 3R) increased.
文摘Catechins in green tea have various useful features including antioxidant activity and preventive effects on metabolic syndrome. Various beverages that are enriched with tea catechins are marketed as Foods for Specified Health Uses (FOSHU) in Japan. However, recent reports have indicated that excessive consumption of green tea extracts as a dietary supplement are associated with adverse health effects such as liver disorders. Various catechins and caffeine are constituents of FOSHU tea-based beverages. The amount of catechins in FOSHU products is displayed on labels as total catechin content, but the content of individual catechins are not provided. Although health hazards of FOSHU products have rarely been reported, precise information about the content and types of catechins in FOSHU products is needed to ensure safety. We used high-performance liquid chromatography with a photodiode array (HPLC/PDA) to simultaneously identify and quantify catechins and caffeine in green tea-based popular beverages and FOSHU beverages. This technique allowed simultaneous quantitation of five types of catechins and caffeine in green tea without complicated sample preparation. Epigallocatechin gallate (EGCG) and epigallocatechin EGC were the main catechins in various FOSHU beverages and the concentrations of almost all catechins were higher in FOSHU, than in popular green tea-based beverages. The concentrations of EGCG in green tea-based popular beverages and in FOSHU beverages were 5.4 - 7.3 and 10.2 - 41.9 mg/100mL, respectively, with the highest concentration being in a product named Healthya (approximately 147 mg/bottle). The simultaneous determination of compounds such as catechins and caffeine in FOSHU beverages can help to estimate beneficial and adverse effects to prevent deleterious effects on health and the excessive consumption of FOSHU beverages containing high concentrations of tea catechins should be avoided.
基金supported by China Agriculture Research System(CARS-15-27)Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences.
文摘Background: The diversified and high value-added utilization of cotton by products can promote the sustainable development of modern agriculture. Di erences in potential nutrients among varieties can be explained by variations in the composition and abundance of fatty acids, polyphenols, carbohydrates, amino acids, and organic acids. Therefore, the analysis of metabolite species and relationships in cottonseed is meaningful for the development of cotton byproducts.Results: In this study, the metabolomes of three representative cotton cultivars of di erent species were compared using untargeted GC-TOF/MS analysis. A total of 263 metabolites were identified from 705 peaks, and their levels were compared across cultivars. Principal component analysis and OPLS-DA clearly distinguish these samples based on metabolites. There were significant di erences in the contents of amino acids, carbohydrates, organic acids, flavonoids, and lipids in G. hirsutum TM-1 compared with G. arboreum Shixiya1 and G. barbadense Hai7124. Notably, the bioactive nutrient compound catechin obtained from the di erential metabolites significantly accumulated in TM-1. Furthermore, a comprehensive analysis using catechin and oil-related traits was conducted in core collections of Gossypium hirsutum. The results revealed the reliability of the GC-TOF/MS analysis, as well as that catechin content has a negative association with myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, and total fatty acids.Conclusion: These findings suggest that untargeted GC-TOF/MS analysis could provide a new method for investigating the underlying plant biochemistry of nutrient variation in cottonseed, and that catechin content has a negative association with oil-related traits in cottonseed. This study may pave the way to exploit the value of cotton byproducts.
基金Project (20576029) supported by the National Natural Science Foundation of China
文摘A series of extractants （tert-butylcalix[6]arene, tert-butylcalix[8]arene and octeacetate of tert-butylcalix[8]arene） were synthesized, and their structures were identified by IR and JH-NMR. The distribution behavior of ester catechins monomer in the aqueous and chloroform two-phase system containing one of calixarene was studied. The influences of different extractants, concentration of tert-butylcalix[8]arene and extraction temperature on the partition coefficients and the separation factors were investigated. The experiment results show that tert-butylcalix[8]arene is the best extractant that forms a more stable supramolecular compound with gallocatechin gallate （GCG） than with epigallocathechin gallate （EGCG） or epicatechin gallate （ECG）. When the concentration ofp-tert-butylcalix[8]arene is 3.79 mmol/L, the extraction temperature is 4 ℃, the partition coefficients ofKGCG, KECG, KEGCG are 0.987, 0.629, 0.449, the separation factors of al and a2 are 1.450 and 1.596, respectively. The important factors influencing the extraction properties of calixarene are discovered to be its cavity size and hydrogen bonding.
文摘Objective:To discuss the effect of catechins on myocardial injury and inflammatory factors in rats with coronary heart disease under PI3K/Akt/eNOS signaling pathway.Methods:A total of 50 healthy adult pathogen-free(SPF)-grade SD rats were divided into five groups by random number table method.Except for the blank group,the other four groups were fed with high fat to construct a rat model of coronary artery disease.After the model was successfully constructed,the blank group and the model group were given saline by gavage,the positive group was given 25 mg/kg aspirin by gavage,the low-dose group was given 20 mg/kg catechin by gavage,and the high-dose group was given 60 mg/kg catechin by gavage.The expression levels of PI3K/Akt/eNOS signaling pathway-related proteins,myocardial injury markers,myocardial infarction and myocardial inflammatory factors were observed and compared in the five groups.Results:Overall,there were significant differences in the expression levels of PI3K,p-Akt/Akt,and p-eNOS/eNOS in the five groups of rats(P<0.05);there were significant differences in the expression levels of CK-MB and c Tn I in the five groups of rats(P<0.05);there were significant differences in ischemic area,infarct area,and myocardial infarction range in the four groups of rats,except for the blank group(P<0.05);there were significant differences in the expression levels of IL-1β,IL-18,TNF-α,and ET-1 in the five groups of rats(P<0.05).Conclusion:Catechins can reduce the severity of myocardial injury,reduce the range of myocardial infarction,and reduce myocardial inflammation in rats with coronary heart disease by up-regulating expression level of PI3K/Akt/eNOS signaling pathway-related proteins.Compared with aspirin,high-dose catechins have a more prominent protective effect on the myocardium of rats with coronary heart disease.
基金supported by the National Natural Science Foundation of China (30170239, 30930036)
文摘Epidemiological evidence and experimental studies suggest that drinking green tea is associated with a lower risk of obesity and related diseases. However, the mechanisms of these effects are not clear. In the present study, we investigated the anti-obesity mechanisms of green tea catechins (GTCs) through modulation of peroxisome proliferator activated-receptor (PPAR) pathways in high-fat diet-induced obesity in rats. GTC supplementation significantly attenuated the increased body and liver weights and the elevated serum and liver triglyceride levels. Meanwhile, GTCs increased the PPARγ levels in subcutaneous white adipose tissue (SWAT) and decreased the PPAR levels in visceral white adipose tissue (VWAT). In addition, GTC treatment up-regulated the levels of PPARδ in SWAT, VWAT, and brown adipose tissue and increased the expression of genes involved in fatty acid oxidation in brown adipose tissue. Our results suggest that GTCs exert their anti-obesity mechanism in part by modulating PPAR signaling pathways.
基金jointly supported by grants from the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2012BAD39B00)State Key Laboratory of Animal Nutrition(2004DA125184F1305)+2 种基金the NSFC(307005793110173031110103909)
文摘This study was conducted to investigate the effects of catechins on reproductive performance, antioxidative capacity and immune function of gestating sows. A total of 60 cross-bred（Landrace × Large White） multiparious sows were blocked by body weight, parity and backfact and randomly allocated to 1 of 5 treatments: 0.100,200,300, or 400 mg/kg catechins. Dietary treatments were imposed from mating to d 40 of gestation of sows. At farrowing, litter total born, born alive, dead, and normal-（healthy piglets,>0.85 kg） and low-birth weight piglets（<0.85 kg） were recorded. Within 3.00 ± 0.50 days after farrowing litter size was standardized to 8,00 ± 1.50 piglets within treatment. The piglets were weighed at birth（d 1） and weaning（d 28）. Sows serum samples were obtained from blood samples collected on d 40 of gestation for analyses of glutathione peroxidase（GSH-Px）, superoxide dismutase（SOD）, catalase（CAT）,malondialdehyde（MDA）, hydrogen peroxide（H2 O2）, nitric oxide synthetase（NOS） and nitrogen monoxide（NO）. Our results showed that supplementation of catechins at levels of 200 or 300 mg/kg led to improvements in litter born alive（P < 0.01） and piglet born healthy（P < 0.01） and a decrease in stillborn（P < 0.05） at farrowing when compared with the control. In comparison with the control, catechins at any supplemental levels all enhanced the serum SOD（P < 0.05） and CAT（P < 0.01） activities of sows at farrowing but no obvious differences in the serum GSH-Px and NOS activities were observed in this trial（P > 0.05）. Sows received 200 mg catechin per kg diets showed a reduction（P < 0.05） of the serum MDA level at farrowing compared with all other treatments. Sows received all the levels of catechin showed a reduction（P < 0.05） of serum H2 O2 level compared with sows received the control diet on both d 40 of gestation and farrowing. Our results demonstrated that the catechins may be a potential antioxidant to increase the reproductive performance and antioxidative capacity of sows when it was added into diets during the early gestation.
文摘The catechin Epigallocatechin-3-O-Gallate (EGCG) which is found in of Green Tea extracts (GTE), displays a variety of microbicidal properties. It is largely believed that EGCG inhibits the growth of cariogenic and periodontopathic bacteria. Objective: In this paper we compared the inhibitory activity of EGCG and a commercial GTE on the growth of Veillonella parvula. Chlorhexidine was used as positive control. Methodology: V. parvula ATCC 10790 and a clinical isolate obtained from a periodontal disease patient were cultured in the presence of EGCG or a commercial GTE, and the measurements of bacterial growth inhibition were compared to the values obtained with 0.12 and 0.2% chlorhexidine. Results: Chlorhexidine inhibited bacterial growth, however in contrast to a previous report, neither EGCG nor the GTE showed any effect on bacterial growth. Conclusions: The data show and confirm that chlorhexidine is a growth inhibitor of V. parvula while EGCG and GTE do not display such effect.
文摘The intensity of the bitterness of catechins increases with increased concentration, but the taste palatability decreased in green tea extract. The aim of this study was to investigate whether a blend of tea leaf particles of various sizes would result in a good balance between catechin content and appreciable taste. The control is common tea (CT) with 6 - 10 mm long leaves. Blend tea (BT) was prepared by mixing 5 mm and 120 - 130 mm long tea leaves in a ratio of 3:2. The catechin content of hot water extracts was analyzed by HPLC, and the sensory test was conducted with 99 volunteers. In BT, the total catechin content was significantly higher than that in CT. The sensory test results revealed that BT was less bitter and had more preferable color than CT. More catechins were extracted from BT, but it tasted less bitter. Thus, the recalibration of the tea leaf particle size can result in good balance between catechin content and palatability.
基金Supported by the"Study on High Efficiency Machining and Multiple Utilization Technology of Tea Germplasm Resource"of National Science&Technology Supporting Project(2006BAD06B01)"Data Standard of Perennial and Vegetative Propagation Crop Germplasm Resources as a Share Experimental Unit"of National Fundamental Resources Platform of Science&Technology Project(2005DKA21002-08)~~
文摘Bitter tea is a special kind of tea germplasm in China.The major biochemical components of 24 bitter teas and other 8 Camellia sinensis var.sinensis and 8 C.sinensis var.assamica tea germplasms,which were stored in the China National Germplasm Hangzhou Tea Repository(CNGHTR),were analyzed and evaluated.The results showed that no significant differences of major biochemical components affecting the tea quality were found between bitter tea and common tea.According to the processing suitability index,bitter tea was suitable for the manufacturing of black tea;while according to evolutionary indices such as the composition and content of catechin,bitter tea was similar to C.sinensis var.assamica belonging to the relatively primitive type in evolution.The results of cluster analysis indicated that bitter tea was clustered with C.sinensis var.assamica,so it could be considered to belong to C.sinensis var.assamica.
