Optimization of Supercritical Extraction Process of Laoshan Black Tea by Response Surface Methodology

[Objectives]Laoshan black tea was subjected to supercritical CO_(2) extraction. [Methods]The extraction conditions of Laoshan black tea were studied by an orthogonal experiment and optimized by response surface methodology. [Results] The optimum extraction conditions of black tea extract by supercritical CO_(2) extraction were as follows: extraction pressure 23.53 MPa, extraction time 1.73 h, and extraction temperature 49.75 ℃, with which the extract yield could reach 5.15% theoretically. [Conclusions] Based on the traditional extraction process, a supercritical extraction method optimized by response surface methodology and a unique extraction process were formed, which enriches the extraction processes and methods of natural raw materials.

Black tea in chemo-prevention of cancer and other human diseases

Tea is the most popular functional beverage in the world and has been gaining more and more attention for its health beneficial properties.Among common teas,black tea is consumed more than green tea and oolong tea worldwide.Numerous studies have shown the biological activities of black tea and its polyphenols that include anti-oxidant,anti-tumor,anti-inflammation and metabolic regulation.Tea polyphenols such as theaflavins and catechins are considered to be multifunctional compounds that could be effective in the prevention or treatment of various cancers,cardiovascular disease,chronic inflammation,obesity,metabolic syndrome,and neurodegenerative diseases.In this review,we summarized the up-to-date research and underlying molecular mechanisms of black tea and its polyphenols.©2013 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

High-quality instant black tea manufactured using fresh tea leaves by two-stage submerged enzymatic processing

Repeated thermal treatment could impair the flavor of instant black tea(IBT)as the volatile compounds and characteristic constituents dramatically vary during the manufacturing process.Utilization of fresh leaves as raw material in IBT manufacture at low temperature may become an alternative to conventional extraction methods.This study aimed to improve the quality of IBT using fresh tea leaves by a two-stage enzymatic processing.The influence of combined enzymatic oxidation and extraction conditions for maximal extractable flavour(taste and aroma)characteristics from fresh tea leaves were investigated.The changes of aroma profiles and chemical constituents including theaflavins(TFs),thearubigins(TRs),theabrownines(TBs)and TRs/TFs ratio in converted tea brews under two-stage enzyme catalyzed fermentation and extraction conditions were further compared between different treatments,based on which the optimised conditions were determined.During the two-stage enzymatic processing,75 kinds of volatile compounds were identified in all processed samples,and the contents of TFs,TRs,TBs and TRs/TFs ratio could be optimized by adjusting different procedures and parameters.The overall properties of final product were compared with two types of commercial IBT.High quality IBT with desired properties and antioxidant activity can be manufactured using fresh tea leaves by two-stage enzymatic processing approach.

Black tea markets worldwide: Are they integrated?

Global tea consumption has risen significantly alongside rapid expansion of international trade in recent years.However,few studies have systematically examined the relationship among the major tea markets worldwide.Using weekly data from 2012-2019,this study empirically analyzed the price series of the world’s major black tea auction markets.The estimation results showed that these markets are connected,even though heterogeneities vary.This finding holds not only for regional markets but also for international markets.The findings offer important implications for tea-producing countries with millions of smallholder farmers.

Chemopreventive Effects of Black Tea Polyphenols in Mouse Skin Model of Carcinogenesis

In the present investigations, the antitumorigenic effect of black tea polyphenols (BTP) in twcrstage mouse skin model of carcinogenesis was studied. The animals were initiated with a single 'subcarcinogenic' topical dose (52 μg/200 μl acetone ) of 7, 12-dimethylbenzanthracene (DMBA). To evaluate the anti-tumour initiating activity, BTP was topically applied twice a week for three weeks prior to DMBA application, followed by topical treatment with 12-o-tetradecanoyl phorbol-13-acetate (TPA) (5 μg/200 μl acetone, 2x/wk. ) as promoter. For evaluation of antitumor promoting activity, BTP was applied prior to each treatment of TPA. BTP application showed marked inhibitory effect as antitumour initiator as well as antitumour promoter in mouse skin medel of two-stage carcinogenesis. Since initiation involves genetic pathway and tumour promotion involves epigenetic pathway, it seems that BTP exerts its antitumorigenic effect by altering both genetic and epigenetic pathways

Comparative Study on Functional Properties of Mulberry Black Tea Fermented by Phellinus igniarius and Eurotium cristatum

[Objectives]To compare functional properties of mulberry black tea fermented by Phellinus igniarius and Eurotium cristatum.[Methods]The functional components of mulberry black tea fermented by P.igniarius and E.cristatum,the deep processing and health care effects of two probiotic fungi were explored.[Results]The polysaccharide content in the tea fermented by P.igniarius was the highest at 0.410 mg/mL,and the hydroxyl radical scavenging rate was the strongest,reaching 60.31%;the content of flavonoids in the tea fermented by E.cristatum was the highest,reaching 60.65μg/mL,and the content of polysaccharides was 83.17%higher than that of mulberry black tea,reaching 0.279 mg/mL.[Conclusions]The mulberry black tea fermented by P.igniarius and E.cristatum has improved in different functional components,and has its own advantages in aroma and mouthfeel,so it has certain research value and market prospect.

Degradation of black tea theaflavin through C-ring cleavage by gut microbiota

Increasing evidence has shown that gut microbiota plays important roles in metabolizing large molecular polyphenols to bioavailable and bioactive microbial metabolites.Theaflavin(TF)is one of the major color compounds in black tea and has demonstrated anti-inflammation,antioxidant,and anticancer effects properties.However,little is known about the metabolism of TF by gut microbiota in vivo.In this study,following the administration of TF to mice,the C-ring cleavage metabolites,dihydro-and tetrahydro-theaflavin(DH-TF and TH-TF)were detected in mouse feces by LC-MS and validated by authentic standards from in situ chemical reaction.The observation of the C-ring cleavage metabolites in TF-treated conventionalized mice but not in germ-free(GF)mice confirmed the role of gut microbiota in cleaving the C-rings of TF.The detection of DH-TF from the anaerobic incubation of TF with catechin-converting gut bacteria,Eggerthella lenta(Eggerth),suggested that the microbes with the capacity to cleave the C-ring of catechins were able to metabolize TF following the same mechanism.Additionally,three small phenolic metabolites were detected in mouse feces,and one of them was primarily detected in SPF mice not GF mice,which revealed that TF,subsequent to the cleaved C-ring,can be further metabolized into smaller phenolic metabolites by gut microbiota.Dose-dependent production of these metabolites were observed from the administration of 100 mg/kg to 400 mg/kg body weight of TF.In conclusion,gut microbiota can metabolize TF to the open-ring metabolites and the phenolic metabolites through the C-ring cleavage in mice.

Potential prebiotic effects of nonabsorptive components of Keemun and Dianhong black tea:an in vitro study

Black tea is a healthy and popular tea beverage.However,its main bioactive compounds(theaflavins and thearubigins)are not easily absorbed.The aim of this study was to investigate the modulation of intestinal microbiota by the nonabsorptive components of Keemun black tea(KBT)and Dianhong black tea(DBT),and fructooligosaccharide(FOS)was selected for use in the control group.KBT,DBT,and FOS significantly increased total short-chain acid production.Specifically,FOS treatment predominantly increased the production of acetic acids and black tea treatments increased the production of acetic,propionic,and butyric acids at similar rates.Moreover,FOS exerted a strong bifidogenic effect after 24 h of fermentation;KBT and DBT increased the abundance of the beneficial genus Bacteroides and Roseburia.In summary,the nonabsorptive components of KBT and DBT could serve as novel prebiotics,the underlying mechanisms of which are quite different from those of FOS.

Gene expression profiling of HepG_(2) cells after treatment with black tea polyphenols

This study aimed to determine the effects of black tea polyphenols on gene expression in hepatocellular cancer cells.The total RNA from HepG_(2) hepatocellular cancer cells treated with black tea polyphenols was subjected to Human 14K cDNA microarray analysis.Real-time PCR and Western blot analysis were conducted to verify microarray data.Black tea polyphenols treatment at the dose of 20 mg/L,40 mg/L or 80 mg/L for one to three days inhibited the growth of HepG_(2) cells in a dose and time dependent manner.A total of 48 genes showed more than two-fold change after black tea polyphenols treatment,including 17 upregulated genes and 31 downregulated genes,and they were involved in the regulation of cell growth,cell cycle,apoptosis,signaling,angiogenesis,tumor invasion and metastasis.Real-time PCR analysis of the selected genes showed that their mRNA expression changes were consistent with the microarray data.In addition,Western blot analysis of the selected genes showed that their protein expression changes were consistent with mRNA expression.In conclusion,gene expression profiles provide comprehensive molecular mechanisms by which black tea polyphenols exerts growth inhibition effects on cancer cells.The novel molecular targets identified in this study may be further exploited as therapeutic strategies for hepatocellular cancer.

Relationship between the price of green tea and black tea of the world’s major tea countries

Black tea and green tea are the most important tea in the world.In this paper we analyze the relationship of the world green price and black tea price.The results show that:in the world tea markets,the world black tea price and the world green tea price have no co-integration,independent of the curve segmentation.In the major green tea countries,there are co-integration relationships between China and Japan,China and Brazil,Japan and Brazil,while Vietnam has a first-order stationary sequence.In the major black tea countries,Sri Lanka and India have no co-integration,Sri Lanka and Indonesia no co-integration,India and Indonesia no co-integration,Sri Lanka and Kenya have co-integration,India and Kenya have co-integration,Kenya and Indonesia have co-integration.

Gas chromatographic method for the determination of hexaconazole residues in black tea

A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (GC-NPD) for the identification and quantitation of hexaconazole. The most appropriate solvent mixture for extracting hexaconazole residues from black tea was n-hexane:acetone at 1:1 (v/v). The extract was cleaned up by adsorption column chromatography using activated florisil. Performance of the method was assessed by evaluating quality parameters such as recovery value, repeatability, reproducibility, linearity and limits of detection and quantitation. When the method was assessed for repeatability, the percentage of recovery ranged between 86% and 96% while the relative standard deviation was between 0.30% and 2.35%. In studies on reproducibility the recovery ranged from 81% to 85% and relative standard deviation from 1.68% to 5.13%, implying that the method was reliable. A field trial was conducted to verify the application of this method with real samples. Results prove that the validated method was suitable for extracting hexaconazole residues.

The Joint Use of Electronic Nose and Electronic Tongue for the Evaluation of the Sensorial Properties of Green and Black Tea Infusions as Related to Their Chemical Composition

The objectives of the present study were to determine the effects of the brewing method on the amount of the major catechins, methylxanthines, total polyphenols and antioxidant capacity in green and black teas, and to correlate the chemical composition of tea infusions to their sensorial properties by the combined use of the electronic nose and tongue. For this purpose, tea infusions were prepared from 7 green teas and 6 black teas using different extraction times (3 - 5 and 10 min). The extraction of total polyphenols and catechins was increased by prolonging the infusion time from 3 - 5 to 10 min, while the caffeine amounts did not increase. The antioxidant activity of teas was well correlated with polyphenol content. Electronic tongue and electronic nose were able to discriminate green teas from black teas on the basis of their sensorial properties. Considering the taste, green teas were characterized by astringency and aftertaste-astringency and this sensation was increased by prolonging the infusion time;black teas were perceived as more bitter, sour, salty and the extraction time affected the astringent sensation. The aroma of green and black teas was discriminated by specific sensors and the increase of the extraction time produced more richly flavoured infusions. This work adds information about correlation between sensorial properties, antioxidant capacity and chemical composition of green and black teas.

In vitro anti-hyaluronidase activity of Sri Lankan low grown orthodox orange pekoe grade black tea(Camellia sinensis L.)

Objective:To access the anti-hyaluronidase activity of Sri Lankan low grown orthodox orange pekoe(OP) grade black tea with a view to develop an anti-aging skin formulation.Methods:Five concentrations(0.125,0.250,0.500,1.000 and 2.000 mg/mL) of black tea brew(BTB) were made using a freeze dried sample of Sri Lankan low grown orthodox OP grade black tea which was prepared according to international organization for standardization specification.Epigallocatechin gallate(EGCG) was used as the reference agent(concentrations tested:0.012,0.025,0.050,0.100 and 0.200 mg/mL).Anti-hyaluronidase activity of BTB and EGCG in vitro were ascertained spectrometrically using hyaluronic acid(from rooster comb)and bovine testicular hyaluronidase.Results:The results revealed that BTB had moderate[IC_(50)=(1.09±0.12) mg/mL]and dose dependent(r^2=0.94) anti-hyaluronidase activity.EGCG also exhibited dose dependent(r^2=0.93,P<0.05) anti-hyaluronidase activity which was superior[IC_(50)=(0.09±0.00) mg/mL]to BTB.Conclusions:Sri Lankan low grown orthodox OP gradc black tca has promising antihyaluronidase activity in vitro and has the potential to be used as an anti-aging cosmaceutical.In addition,it may prove useful as a beverage in the management of allergy,some joint diseases and cnvenomation.

Determination of Vitamin B₁₂in Chinese Black Tea Leaves

We determined vitamin B12 content of Chinese black tea leaves using a microbiological assay based on Lactobacillus delbrueckii ATCC 7830. Trace levels (0.25 - 0.69 μg/100g dry weight) of vitamin B12 were detected in Pu’er, Fu, and Brick tea leaves. However, vitamin B12 content (0.06 - 1.37 μg/100g dry weight) of Ryubao tea leaves significantly varied. To determine whether Chinese black tea leaves contain vitamin B12 or other corrinoid compounds that are inactive in humans, corrinoid compounds were purified from Ryubao tea by an immunoaffinity column chromatography and vitamin B12 was identified by liquid chromatography-electrospray ionization/tandem mass spectrometry. Vitamin B12 content in the tea drink prepared from Ryubao tea leaves was very low (0.8 ng/100mL). Our results indicate that Chinese black tea is usually not a good source of B12, although Ryubao tea leaves with the highest B12 content may be utilized as a source of this vitamin for vegerarians.

Optimization of Response Surface of Ultrasonic-assisted Extraction of Rizhao Black Tea

[Objective] The aim was to determine the optimal technology for ultrasonic-assisted extraction of black tea was determined. [Method] Taking Black Tea as materials, the Box-Behnken response surface design method of tea polyphenols ultrasonic-assisted extraction process optimization was applied. The regression optimization model of the ethanol volume fraction, ultrasonic time, and ultrasonic temperature, ethyl acetate extract stalling time and tea polyphenols was established. [Result] The influence of four factors on the black tea polyphenol solvents affecting size was as follows: ultrasonic time > ethanol volume fraction > stalling extraction time > ultrasound temperature. The best extraction process was ultrasonic time 80 min, volume fraction of 88.99% ethanol, extraction time 89.97 min, ultrasonic temperature of 80 ℃. At the optimized technical parameters, the black tea phenolic extraction yield can be as high as 73.50%. [Conclusion] The study provided theoretical basis for the development of tea leaves and black tea.

Optimization of Withering and Fermentation Parameters during the Manufacture of Congou Black Tea of Sichuan

A central composite design(CCD),with three variables and three levels,was used to optimize withering and fermentation processing during manufacture of Congou black tea of Sichuan.The three independent variables were withering time,fermentation time and fermentation temperature.Each factor was set by three levels.The responses were predicted by analysis of the regression equation.In the study,the models of regression equation were significant by the analysis of variance(ANOVA).The second-order response surface figures were showed that interaction term is correlated with the response.Optimal process parameters for the maximum of TF and TR formation were obtained at withering time of 12 hours,fermentation time of 2 hours,and fermentation temperature of 30℃.The predictions of TF and TR formation were 0.52% and 3.98%.The results obtained in this study showed that the CCD and Response Surface Methodology(RSM) could be an effective tool to optimize the process parameters of Congou black tea manufacture.

An essential role of endothelium-derived nitric oxide in vasorelaxations induced by black tea polyphenols

Green tea has received much attention as protective agent against cardiovascular disease and cancer,the two primary targets of preventive medicine.Since our first demonstration in 1999 of the involvement of endothelium-derived nitric oxide in the acute vasodilator effect of green tea polyphenols,several new vascular protective effects of green tea catechins have been identified.Theaflavins are another class of polyphenol pigments found in black tea,however,little is known about their bioactivity in the vascular system.We have recently demonstrated that black tea and its theaflavins cause relaxations of rat aortas via endothelial nitric oxide-dependent mechanisms and the tea polyphenols are very effective in protecting endothelial function agonist oxidative stress.The present results support the vascular benefit of consumption of black tea,which is equal to that of drinking green tea in terms of their endothelial cell protection and antioxidant capacity.

Effect of Black Tea Polyphenol on Cell-ECM Interaction and MMP

Tea is one of the most widely consumed beverages in the world. Black tea, obtained from the leaves of Camellia sinensis is the preferred beverage in India and in most western countries. Epidemiological studies on black tea and cancer are limited. However, preliminary studies indicate a positive correlation between black tea consumption and a lower incidence of breast and ovarian cancer. In the present communication, we wanted to see the effect of black tea extract and the polyphenol theaflavin on cell-ECM interaction, MMP activity etc. to strengthen the anti-cancer effect of black tea.

Selected Inorganic Nutrients in Black Tea from Three Tea Growing Agro-Ecological Areas in Kenya

The tea plant absorbs dissolved nutrients from soils for its normal growth and development, though to different extents. Nutrients play vital roles in various metabolic processes, their deficiency or excess being deleterious to living organisms. A study was carried out to quantitatively assess the inorganic nutrient content (K, P, Ca, Mn, Fe, Zn and Cu) of twelve black tea samples sourced from Murang’a, Meru and Kisii tea growing agro-ecological areas in Kenya. K and P were quantified using a flame photometer and a UV-Vis spectrophotometer respectively whereas Ca, Mn, Fe, Zn and Cu were quantified using an Atomic Absorption Spectrophotometer (AAS). The general accumulation pattern of the inorganic nutrients in the tea samples was established to be;K (1.6% ± 0.05%-2.1% ± 0.01%) > P (0.30% ± 0.01%-0.37% ± 0.04%) > Ca (0.16% ± 0.01%-0.62% ± 0.03%) > Mn (0.07% ± 0.009%-0.13% ± 0.004%) > Fe (136 ± 8-320 ± 5 μg/g) > Zn (27 ± 1-39 ± 7 μg/g) > Cu (10 ± 3-16 ± 1 μg/g). Statistically significant differences (p < 0.05) were observed in the inorganic nutrient contents of the black tea from the different tea factories as well as agro-ecological areas. These data demonstrate the tea plant’s ability to accumulate the studied nutrients, further underlining tea consumption as a potential dietary source of the nutritionally essential inorganic nutrients.

The Design and Implementation of Black Tea Traceability System Based on UHF RFID

In order to realize the whole process of consumer- producer bidirectional traceability and distinguish the true from the false,according to Yinghong 9,planting,processing and circulation situation,we introduce UHF RFID and Network information technology,to design and develop the UHF RFID black tea traceability system.The system adopts.NET technology,uses Microsoft Visual Studio 2010 + VB.NET,Microsoft SQL SERVER 2005,T-SQL language for development and design,and uses the network architecture of C /S combined with B /S,to randomly generate ID with 20 bit code and label,thereby forming the only corresponding relation and pointing to the corresponding batch and product types.The technology mode using three-layer structure for development realizes the functions of data collection,tracing,sharing and query.The data and business processing are concentrated on the server,simplifying the development,use and maintenance of system.We build and implement Yinghong 9 black tea traceability system,to the needs of government,the public and the producers for Yinghong 9 brand protection,product quality tracking and market regulation.