Fermented Black Tea Research Articles

Effect of Kombucha on gut-microbiota in mouse having non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver disorders. Possible links have been recently found between the gut-microbiota and the host metabolism in development of NAFLD and obesity. Therefore, understanding the changes in intestinal microbiota during the progression of NAFLD, is important. In this study, the effect of Kombucha tea (KT), obtained by microbial fermentation of sugared black tea, was investigated on gut-microbiota during the progression of NAFLD. The results indicated a decrease in Erysipelotrichia class by treatment with KT in comparison to the methionine/choline-deficient (MCD)-fed db/db mice. Allobaculum, Turicibacter, and Clostridium genera, were only detected in MCD-fed db/db mice and were decreased after treatment with KT, whereas Lactobacillus was more abundant in MCD + KT-fed mice than in MCD only-fed mice and Mucispirillum, was found only in the MCD + KT-fed mice group. Our results demonstrated that the change of intestinal microbiota was influenced by KT intake, contributing to combat NAFLD.

Prediction of Congou Black Tea Fermentation Quality Indices from Color Features Using Non-Linear Regression Methods

Fermentation is the key process to produce the special color of congou black tea. The machine vision technology is applied to detect the color space changes of black tea’s color in RGB, Lab and HSV, and to find out its relevance to black tea’s fermentation quality. And then the color feature parameter is used as input to establish physicochemical indexes (TFs, TRs, and TBs) and sensory features’ linear and non-linear quantitative evaluation model. Results reveal that color features are significantly correlated to quality indices. Compared with the other two color models (RGB and HSV), CIE Lab model can better reflect the dynamic variation features of quality indices and foliage color information of black tea. The predictability of non-linear models (RF and SVM) is superior to PLS linear model, while RF model presents a slight advantage over the classic SVM model since RF model can better represent the quantitative analytical relationship between image information and quality indices. This research has proved that computer image color features and non-linear method can be used to quantitatively evaluate the changes of quality indices (e.g. sensory quality) and the pigment during black tea’s fermentation. Besides, the test is simple, fast, and nondestructive.

Differentiation of black tea infusions according to origin, processing and botanical varieties using multivariate statistical analysis of LC-MS data

A data set of sixty samples of diverse black tea were collected and analysed using high-performance liquid chromatography-mass spectrometry (HPLC-MS) methods. Chemical variations of black tea infusions depending on origin, botanical variety, and processing were investigated employing various multivariate statistical techniques including principal component analysis (PCA), hierarchical cluster analysis (HCA), partial least squares discriminant analysis (PLS-DA) and analysis of variance (ANOVA).In particular, PLS-DA allowed identification of a variety of marker compounds responsible for differences among black teas of different origin, plant variety and processing methods used.Among most variable compounds are catechins, derivatives of quercetin, apigenin, quinic acid, and kaempferol. Rutin, epigallocatechin gallate (EGCG), quinic acid and theaflavin (TF) were contributing to most variances. Products of black tea fermentation (theaflavin, theasinensin, and theacitrin derivatives) contributed to PLS-DA associated to the processing of black tea.

Novel Theaflavin-Type Chlorogenic Acid Derivatives Identified in Black Tea.

Consumption of black tea contributed to many health benefits including the prevention of heart disease and certain types of cancer. However, the chemical composition of black tea has not been fully explored. Most studies have examined different interactions between the four major tea catechins, and limited studies have investigated the interaction between catechins and other components in tea. In the present study, we tested our hypothesis that the ortho-dihydroxyl structure of chlorogenic acid (CGA) could react with the vic-trihydroxy structure of (-)-epigallocatechin 3-gallate (EGCG) and (-)-epigallocatechin (EGC) to generate theaflavin-type of compounds during black tea fermentation. The reaction between CGA and EGCG or EGC was catalyzed by horseradish peroxidase (POD) in the presence of H2O2. Two theaflavin-type compounds EGCG-CGA and EGC-CGA were purified using a Sephadex LH-20 column. Their structures were elucidated on the basis of the analysis of their MS and 1D- and 2D-NMR spectroscopic data. Furthermore, the existence of these two novel compounds was characterized by LC/MS/MS analysis. We also found that EGCG-CGA and EGC-CGA had very similar inhibitory effects on the growth of human colon cancer cells with that of theaflavin 3,3'-digallate. These findings shed light on the interactions between the major bioactive compounds, catechins, and other minor compounds in tea. The confirmation of the presence of this type of reaction in black tea may provide more understanding of the complexity of black tea chemistry.

Improving the quality of fermented black tea juice with oolong tea infusion

Fresh tea leaves were crushed into juice and then fermented (oxidation) to obtain fermented black tea juice, which can be used to prepare black tea beverage. The effects of addition of oolong tea infusion or tossing of tea leaves on the sensory quality and theaflavins (TFs) concentration of fermented black tea juice were investigated. The results showed that both addition of tea infusion and tossing of fresh tea leaves increased the TFs/thearubigins (TRs) ratio and improved the sensory quality of fermented black tea juice. The TFs/TRs ratio was found to be significantly correlated with the scores for flavor (r=0.98), mouth feel (r=0.94), and overall acceptability (r=0.91) of the fermented black tea juices from different processes. This result suggested that a relatively high concentration of catechins and stepwise enzymatic oxidation were the crucial factors that increased the TFs/TRs ratio and improved the sensory quality. The combination of adding tea infusion and tossing fresh tea leaves greatly improved the quality of the fermented black tea juice by markedly increasing the TFs/TRs ratio (87%). Results of the present study provided useful information for improving the quality of fermented black tea juice.

Associations between Repeated Measures of Agricultural Pesticide Exposures and Pubertal Markers in a Cohort of Girls

Tea is a widely consumed beverage in the world, and has become an important agricultural product. It has dozens of varieties, such as unfermented green tea, semifermented oolong tea, and fermented black tea. The major constituents in tea are polyphenols, alkaloids, volatile oils, polysaccharides, amino acids, lipids, vitamins, and inorganic elements, etc. Recently, water-soluble tea polysaccharides (TPSs) have attracted scientists’ attention. The polysaccharide from approximately 1.5% to nearly 13%. It has been demonstrated that TPSs have many bioactivities, such as reducing blood sugar levels, immunological, antiradiation, antiblood coagulation, anticancer, anti-HIV, and hypoglycemic activities. This chapter introduces the preparation of TPS, its structural features, chemical modifications, biological activities, and structure–bioactivity relationship.

Prediction of black tea fermentation quality indices using NIRS and nonlinear tools.

Catechin content, the ratio of tea polyphenols and free amino acids (TP/FAA), as well as the ratio of theaflavins and thearubigins (TFs/TRs) are important biochemical indicators to evaluate fermentation quality. To achieve rapid determination of such biochemical indicators, synergy interval partial least square and extreme learning machine combined with an adaptive boosting algorithm, Si-ELM-AdaBoost algorithm, were used to establish quantitative analysis models between near infrared spectroscopy (NIRS) and catechin content and between TFs/TRs and TP/FAA, respectively. The results showed that prediction performance of the Si-ELM-AdaBoost mixed algorithm is superior than that of other models. The prediction results with root-mean-square error of prediction ranged from 0.006 to 0.563, the ratio performance deviation values exceeded 2.5, and predictive correlation coefficient values exceeded 0.9 in the prediction model of each biochemical indicator. NIRS combined with Si-ELM-AdaBoost mixed algorithm could be utilized for online monitoring of black tea fermentation. Meanwhile, the AdaBoost algorithm effectively improved the accuracy of the ELM model and could better approach the nonlinear continuous function.

Synergistic Application of Black Tea Extracts and Lactic Acid Bacteria in Protecting Human Colonocytes against Oxidative Damage.

In view of the potential of lactic acid bacteria (LAB) to enhance the antioxidant activity of food products, this work explored the effectiveness of LAB fermented black tea samples in alleviating H2O2-induced oxidative stress in human colonocytes. The antioxidant capacity of tea samples was evaluated in terms of cyto-protectiveness, mitochondria membrane potential (Δψm)-stabilizing activity, ROS-inhibitory effect, and antioxidant enzyme-modulating activity. The effect on oxidative DNA damage and repair was studied in CCD 841 by comet assay. Results showed that the protective effect of tea pretreatment was more pronounced in normal cells (CCD 841) than in carcinomas (Caco-2), and fermented samples were invariably more effective. Higher cell viability and Δψm were maintained and ROS production was markedly inhibited with tea pretreatment. The fermented tea samples also remarkably stimulated DNA repair, resulting in fewer strand breaks and oxidative lesions. Our study implied that LAB fermentation may be an efficient way to enhance the antioxidative effectiveness of black tea flavonoid-enriched foods.

Effects of blending wheatgrass juice on enhancing phenolic compounds and antioxidant activities of traditional kombucha beverage

Traditional kombucha is a fermented black tea extract and sugar. Sweetened black tea (10% w/v) and wheatgrass juice (WGJ) were mixed in various ratios and used as fermentation substrate for enhancing phenolic compounds and antioxidant activity. Starter, comprising of yeast (Dekkera bruxellensis) and acetic acid bacteria (Gluconacetobacter rhaeticus and Gluconobacter roseus), was inoculated at 20% (v/v), and fermented statically at 29 ± 1°C for 12 days. The results showed that the total phenolic and flavonoid contents and antioxidant activity of the modified kombucha were higher than those of traditional preparations. All WGJ-blended kombucha preparations were characterized as having higher concentrations of various phenolic compounds such as gallic acid, catechin, caffeic acid, ferulic acid, rutin, and chlorogenic acid as compared to traditional ones. Addition of WGJ resulted in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability of kombucha being > 90%, while the oxygen radical absorbance capacity increased from 5.0 μmol trolox equivalents/mL to 12.8 μmol trolox equivalents/mL as the ratio of WGJ increased from 0% to 67% (v/v). The highest antioxidant activity was obtained using a 1:1 (v/v) black tea decoction to WGJ ratio and 3 days of fermentation, producing various types of phenolic acids. These results suggest that intake of fermented black tea enhanced with wheatgrass juice is advantageous over traditional kombucha formulas in terms of providing various complementary phenolics and might have more potential to reduce oxidative stress.

Fermentation of Plant Material – Effect on Sugar Content and Stability of Bioactive Compounds

Extraction is a method often used to obtain products rich in bioactive compounds from plant material. Most of the solvents used for the polyphenols extraction simultaneously extract also sugars, undesirable as a component of health–promoting food. Fermentation might be a simple, cheap and efficient way of sugar elimination. In our study, black tea and goji berries, both known for their health benefits, were used and alcoholic fermentation by Saccharomyces cerevisiae was carried out to eliminate sugars. In the course of fermentation the concentration of polyphenols, L–theanine and carotenoids was evaluated in order to verify the preservation of selected bioactive compounds. Decreases in sugar content, formation of ethanol and yeasts growth were monitored during fermentation. The fermentation of black tea decreased the sugar concentration by 84% within 6 h without decreasing total polyphenols and L–theanine contents. Goji berry fermentation yielded a sugars decrease of 87% within 24 h, without decrease in polyphenol content. However, carotenoid content was reduced by 17%. The study showed that fermentation was an effective way to decrease sugar content in plant extracts, and therefore it might be a pertinent step to concentrate bioactives.

Myocardial potency of Bio-tea against Isoproterenol induced myocardial damage in rats.

Kombucha (Bio-tea) is a beverage produced by the fermentation of sugared black tea using a symbiotic association of bacteria and yeasts. Traditional claims about Kombucha report beneficial effects such as antibiotic properties, gastric regulation, relief from joint rheumatism and positive influence on the cholesterol level, arteriosclerosis, diabetes, and aging problems. The present investigation was carried out to understand the preventive effect of Kombucha on heart weight, blood glucose, total protein, lipid profile and cardiac markers in rats with myocardial damage induced using Isoproterenol. As Bio-tea is produced by fermenting tea, the parameters were compared in rats pre-treated with normal black tea and Bio-tea for 30days followed by subcutaneous injection of Isoproterenol (85mg/kg body weight). Normal rats as well as Isoproterenol induced myocardial infarcted rats were also used, which served as controls. Isoproterenol induced myocardial infarcted control rats showed a significant increase in heart weight, blood glucose and cardiac markers and a decrease in plasma protein. Increased levels of cholesterol, triglycerides, low density lipids (LDL) and very low density lipids (VLDL) were also observed, while the high density lipid (HDL) content decreased. Bio-tea showed a higher preventive effect against myocardial infarction when compared to tea, as was observed by the significant reduction in heart weight, and blood glucose and increase in plasma albumin levels. Bio-tea significantly decreased cholesterol, triglycerides, LDL and VLDL while simultaneously increasing the levels of HDL. Similarly a decrease in leakage of cardiac markers from the myocardium was also observed.

Effect of Kombucha, a fermented black tea in attenuating oxidative stress mediated tissue damage in alloxan induced diabetic rats

Diabetic complications associated with increased oxidative stress can be suppressed by antioxidants. In the present study we investigated the antidiabetic and antioxidant effects of Kombucha (KT), a fermented black tea, in comparison to that of unfermented black tea (BT), in ALX-induced diabetic rats. ALX exposure lowered the body weight and plasma insulin by about 28.12% and 61.34% respectively and elevated blood glucose level and glycated Hb by about 3.79 and 3.73 folds respectively. The oxidative stress related parameters like lipid peroxidation end products (increased by 3.38, 1.7, 1.65, 1.94 folds respectively), protein carbonyl content (increased by 2.5, 2.35, 1.8, 3.26 folds respectively), glutathione content (decreased by 59.8%, 47.27%, 53.69%, 74.03% respectively), antioxidant enzyme activities were also altered in the pancreatic, hepatic, renal and cardiac tissues of diabetic animals. Results showed significant antidiabetic potential of the fermented beverage (150 mg lyophilized extract/kg bw for 14 days) as it effectively restored ALX-induced pathophysiological changes. Moreover, it could ameliorate DNA fragmentation and caspase-3 activation in the pancreatic tissue of diabetic rats. Although unfermented black tea is effective in the above pathophysiology, KT was found to be more efficient. This might be due to the formation of some antioxidant molecules during fermentation period.

A Literature Review of Some Deseases Can Cured With Tea Component

Tea (Camellia sinensis) very rich in flavonoids and one of the important plant in the world. The six major flavan-3-ols occurring in tea are catechin (C), gallocatechin (GC), epicatechin (EC), epigallocatechin (EGC), epicatechin-3-gallate (EGG), and epigallocatechin-3-gallate (EGCG). Theaflavins and thearubigins are a group of polyphenol pigments formed during the fermentation of black tea This paper identified the deaseas can cured with the tea properties by literature reviewed. Besides the tea component itself, cancer can prevent with synergyc with capsicum. At a ratio of 25 parts green tea concentrate to 1 part Capsicum preparation, the resultant product exhibited efficacy in the killing of cancer cells in culture 100-times that of green tea on a weight basis. The tea property/polyphenols can use for cancer such as pancreatic cancer, tumor, immortalized keratinocytes and skin cancer cell lines, breast cancer, breaks in bone marrow cells of leukaemic, reduce skin tumor cell, anti-inflammatory, prevent influenza infection in children. Tea pyphenols in black tea nor green tea can reduce human cancer cells, tumor, breast cancer, anti-inflammatory, leukemia and to prevent influenza. EGCG to treat pancreatic cancer, skin cancer, reduce skin tumor cell and keratinocytes. EC for anticancer therapy against acute myeloid leukemia and TF, TR for treating human skin cancer cells.

Antimicrobial effect of Kombucha analogues

Kombucha is a traditional refreshing beverage obtained by the fermentation of sugared tea with a powerful symbiosis of acetic bacteria and yeasts. This drink has been intensively consumed during a long time worldwide for its prophylactic and therapeutic properties. In the present study, we have screened traditional fermented black tea for antibacterial and antifungal activity against Gram (+) and Gram (−) human pathogenic bacteria (n = 7) and candida yeasts (n = 7) using agar diffusion method. Additionally, antimicrobial activity of five new fermented beverages produced from the following medicinal herbal extracts: Thymus vulgaris L., Lippia citriodora, Rosmarinus officinalis, Foeniculum vulgare and Mentha piperita noted as Kombucha-analogues were investigated, using agar diffusion method. Strong antimicrobial potentials were found with the new fermented beverages, particularly those prepared by the fermentation of L. citriodora and F. vulgare infusions, exhibiting the most important inhibition zone observed against the Candida strains tested (Candida glabrata, Candida tropicalis, Candida sake, Candida dubliniensis and Candida albicans). In view of their antimicrobial activity demonstrated against a range of pathogenic bacteria and against a number of clinical Candida species, the fermented L. citriodora and F. vulgare may be very healthful.

Black Tea Theaflavins Inhibit Formation of Toxic Amyloid-β and α-Synuclein Fibrils

Causal therapeutic approaches for amyloid diseases such as Alzheimer's and Parkinson's disease targeting toxic amyloid oligomers or fibrils are still emerging. Here, we show that theaflavins (TF1, TF2a, TF2b, and TF3), the main polyphenolic components found in fermented black tea, are potent inhibitors of amyloid-β (Aβ) and α-synuclein (αS) fibrillogenesis. Their mechanism of action was compared to that of two established inhibitors of amyloid formation, (-)-epigallocatechin gallate (EGCG) and congo red (CR). All three compounds reduce the fluorescence of the amyloid indicator dye thioflavin T. Mapping the binding regions of TF3, EGCG, and CR revealed that all three bind to two regions of the Aβ peptide, amino acids 12-23 and 24-36, albeit with different specificities. However, their mechanisms of amyloid inhibition differ. Like EGCG but unlike congo red, theaflavins stimulate the assembly of Aβ and αS into nontoxic, spherical aggregates that are incompetent in seeding amyloid formation and remodel Aβ fibrils into nontoxic aggregates. When compared to EGCG, TF3 was less susceptible to air oxidation and had an increased efficacy under oxidizing conditions. These findings suggest that theaflavins might be used to remove toxic amyloid deposits.

Evaluation of the antioxidant effects of four main theaflavin derivatives through chemiluminescence and DNA damage analyses

Theaflavins (TFs) are the dimers of a couple of epimerized catechins, which are specially formed during black tea fermentation. To explore the differences among four main TF derivatives (theaflavin (TF(1)), theaflavin-3-gallate (TF(2)A), theaflavin-3'-gallate (TF(2)B), and theaflavin-3,3'-digallate (TF(3))) in scavenging reactive oxygen species (ROS) in vitro, their properties of inhibiting superoxide, singlet oxygen, hydrogen peroxide, and the hydroxyl radical, and their effects on hydroxyl radical-induced DNA oxidative damage were systematically analyzed in the present study. The results show that, compared with (-)-epigallocatechin gallate (EGCG), TF derivatives were good antioxidants for scavenging ROS and preventing the hydroxyl radical-induced DNA damage in vitro. TF(3) was the most positive in scavenging hydrogen peroxide and hydroxyl radical, and TF(1) suppressed superoxide. Positive antioxidant capacities of TF(2)B on singlet oxygen, hydrogen peroxide, hydroxyl radical, and the hydroxyl radical-induced DNA damage in vitro were found. The differences between the antioxidant capacities of four main TF derivatives in relation to their chemical structures were also discussed. We suggest that these activity differences among TF derivatives would be beneficial to scavenge different ROS with therapeutic potential.

Changes of Constituents and Activity to Apoptosis and Cell Cycle During Fermentation of Tea

Tea is believed to be beneficial for health, and the effects of the fermentation process on its contributions to apoptosis and cell cycle arrest of gastric cancer cells have not been completely investigated. In this study, the chemical components in green tea, black tea and pu-erh tea aqueous extracts were analyzed and compared. The polysaccharide and caffeine levels were substantially higher in the fermented black tea and pu-erh tea, while the polyphenol level was higher in the unfermented green tea. Hence, a treatment of tea aqueous extract and the components, which are emerging as promising anticancer agents, were pursued to determine whether this treatment could lead to enhance apoptosis and cell cycle arrest. In the human gastric cancer cell line SGC-7901, the cell viability and flow cytometry analysis for apoptotic cells indicated effects in a dose-dependent inhibition manner for the three tea treatment groups. The apoptosis rates were found to be elevated after 48 h of treatment with 31.2, 125, and 500 μg/mL of green tea extract, the higher catechins content may be involved in the mechanism. Cell cycle was arrested in S phase in the fermented black tea and pu-erh tea, and the populations were significantly decreased in G2/M phases, possibly due to the oxidation of tea polyphenols, which causes an increase of theabrownins. CCC-HEL-1 normal cells were not sensitive to tea extract. These findings suggest that the fermentation process causes changes of the compounds which might be involved in the changes of cell proliferation inhibition, apoptosis induction and cell cycle arrest.

Oxidation of the Dihydrochalcone Aspalathin Leads to Dimerization

Aspalathin and nothofagin are typical ingredients of unfermented rooibos (Krafczyk, N.; Glomb, M. A. J. Agric. Food Chem. 2008, 56, 3368). During oxidation these dihydrochalcones were degraded to higher molecular weight browning products under aerated and nonenzymatic conditions. In the early stages of browning reactions aspalathin formed two dimers. These two compounds were unequivocally established as atropisomers stemming from oxidative A to B ring coupling. Multilayer countercurrent chromatography (MLCCC) and preparative high-performance liquid chromatography (HPLC) were applied to obtain pure substances. The purity and identity of isolated dimers were confirmed by different NMR experiments, HPLC-DAD-MS, and HR-MS. In parallel to the formation of chromophores during the fermentation of black tea, the formation of aspalathin dimers implies an important mechanistic channel for the generation of color during the processing of rooibos.

Green and black tea are equally potent stimuli of NO production and vasodilation: new insights into tea ingredients involved

Epidemiological studies suggest that consumption of tea is associated with beneficial cardiovascular effects. Since different types of tea are consumed throughout the world, a question of much interest is whether green tea is superior to black tea in terms of cardiovascular protection. We therefore compared the effects of green and black tea on nitric oxide (NO) production and vasodilation and elucidated the tea compounds involved. We chose a highly fermented black tea and determined concentrations of individual tea compounds in both green and black tea of the same type (Assam). The fermented black tea was almost devoid of catechins. However, both teas stimulated eNOS activity and phosphorylation in bovine aortic endothelial cells (BAEC) as well as vasorelaxation in rat aortic rings to a similar extent. In green tea, only epigallocatechin-3-gallate (EGCG) resulted in pronounced NO production and NO-dependent vasorelaxation in aortic rings. During tea processing to produce black tea, the catechins are converted to theaflavins and thearubigins. Individual black tea theaflavins showed a higher potency than EGCG in NO production and vasorelaxation. The thearubigins in black tea are highly efficient stimulators of vasodilation and NO production. Green and black tea compounds induced comparable phosphorylation of eNOS and upstream signalling kinases. Whereas stimulation of eNOS activity by EGCG was only slightly affected by pretreatment of cells with various ROS scavengers, TF3(theaflavin-3',3-digallate)-induced eNOS activity was partially inhibited by PEG-catalase. These results implicate that highly fermented black tea is equally potent as green tea in promoting beneficial endothelial effects. Theaflavins and thearubigins predominantly counterbalance the lack of catechins in black tea. The findings may underline the contribution of black tea consumption in prevention of cardiovascular diseases.

Extract of black tea (pu‐ehr) inhibits postprandial rise in serum cholesterol in mice, and with long term use reduces serum cholesterol and low density lipoprotein levels and renal fat weight in rats

A water-soluble extract of a traditional Chinese fermented black tea, pu-ehr, decomposes bile acid cholesterol micelles. This black tea extract (BTE) was studied to see if it could decrease the postprandial elevation of blood cholesterol levels after a single administration in ddY mice. It was found that BTE (0.3 g/kg) significantly decreased the postprandial rise in blood cholesterol levels after oral administration of cholesterol (130 mg/kg). A non-fermented tea (i.e. green tea) extract did not prevent the postprandial increase in blood cholesterol. In a subsequent study, 5-week-old Sprague-Dawley (SD) rats were fed BTE for 3 weeks, following which a dose-dependent and significant decrease in serum total cholesterol levels (1.36 mmol/L, 0.1% BTE, p < 0.05) was found and also in renal fat weight (0.3% BTE, p < 0.05). LDL cholesterol levels (0.51 mmol/L, 0.1% BTE, p < 0.05) were also significantly decreased. There were no significant changes in the weights of other organs or in the serum levels of other clinical markers. Thus, BTE has a specific antihypercholesterol effect in rodents, which might potentially aid in the management of hyperlipidaemia in man.