CTC Black Tea Research Articles

Optimization of Fermentation Time, Temperature, and Tea Bed Thickness in CFM to Enhance the Biological Composition of CTC Black Tea

Optimization of Fermentation Time, Temperature, and Tea Bed Thickness in CFM to Enhance the Biological Composition of CTC Black Tea

Unveiling the effect of leaf maturity on biochemical constituents and quality of CTC black tea: insights from Northeast India’s commercial cultivars

Unveiling the effect of leaf maturity on biochemical constituents and quality of CTC black tea: insights from Northeast India’s commercial cultivars

Tracing the geographic origin of CTC black tea based on colorimetric sensor array response to taste substances combined with chemometrics

The quality of crush–tear–curl black tea (CTC-BT) varies greatly by geographic origin. Origin traceability is crucial for consumer interest protection, market order regulation, and food safety monitoring. This paper proposes a fast and accurate method for qualitative discrimination of CTC-BT origins and quantitative detection of its key taste-presenting substances. The method involves a simple colorimetric sensor array and ultraviolet–visible spectroscopy. The effects of various variable screening methods on modeling results were compared. A particle swarm optimization–based support vector machine achieved the highest performance in qualitative discrimination, with a correct classification rate of 99.48%. Based on their origin-distinguishing contributions and dose-over-thresholds, seven key taste-presenting substances were screened, namely, theaflavin, caffine, vitexin-2-O-rhamnoside, rutin, epigallocatechin gallate, epicatechin gallate, gallic acid. A least squares-support vector regression model achieved accurate quantification of the seven aforementioned compounds (square root of determination coefficient of prediction >0.9698, residual prediction deviation >2).

Biochemical assessment of CTC-black tea manufactured by bought leaf factories from leaves of small tea growers in Terai, West Bengal

Biochemical assessment of CTC-black tea manufactured by bought leaf factories from leaves of small tea growers in Terai, West Bengal

Comparative studies on the antioxidant, anticancer and anti-inflammatory activities of green tea, orthodox black tea and CTC black tea.

Tea is a natural dietary supplement rich in polyphenols and based on the manufacturing process, their polyphenol content also varies. In the present study, we have compared thein vitroantioxidant, anticancer and anti-inflammatory activities of green tea (GT), orthodox black tea (oBT) and CTC black tea (cBT). The analysis was carried out in 50:50 ethanol:water extracts. The total antioxidant capacity, total polyphenol content and free radical scavenging activity were found to be high in GT samples. HPLC profiling indicated a higher percentage of polyphenols like catechin, epicatechin, epigallocatechin and epigallocatechin-gallate in GT when compared to other samples. The comparison of the anticancer potential was done in breast cancer MDA MB-231 cells and it was found that GT has a higher percentage of cell growth inhibition than oBT and cBT. Anti-inflammatory effects were done in LPS stimulated RAW264.7 macrophage cells and here also GT showed maximum effects. This was confirmed by the lower production of iNOS, reduced level of ROS generation and proinflammatory cytokines such as MCP-1, IL-1ɑ, and IL-6 by GT. To conclude, the order for the biological effectiveness of different teas tested is in the order GT > oBT > cBT.

Therapeutic value of organic and conventional teas in Sri Lanka against microbial agents

Due to its naturally occurring medicinal ingredients known as polyphenols, tea attracts the interest of the pharmaceutical and scientific disciplines. Besides the established antioxidant activity, many phenolic compounds in tea exhibit significant antimicrobial activity. Environmental factors and crop management substantially influence the amount and activity of polyphenols available in tea leaves. In Sri Lanka, there are six main agro-ecological regions where tea is grown using either conventional or organic management. Present study focused to determine the effects of tea production system and their growing region on polyphenol content and antimicrobial properties of made tea. Fresh leaf samples were collected from randomly selected tea estates each for organically certified and conventional from major tea growing regions in Sri Lanka. They were manufactured into CTC black tea using a miniature system. Polyphenol content was assessed by ISO standard method, while the anti-bacterial and anti-fungal properties were evaluated using disk diffusion technique against Escherichia coli ATCC 25922 and clinical pathogen of Aspergillus niger. Polyphenol content, anti-bacterial and anti-fungal properties were significantly different (P<0.05) between the tea production systems and among the growing regions, where organic tea had higher polyphenol content, anti-bacterial and anti-fungal properties than conventional teas. The Southern region tea had greater anti-bacterial and anti-fungal properties probably due to the high polyphenol content, while it was the lowest in Uva region. In conclusion, this research presents preliminary evidence that Sri Lankan teas grown and managed organically have superior antimicrobial properties over conventional teas. To confirm the findings, more investigation using time series measurement in all tea-growing regions is suggested.

20세기 전반기 미국 차 소비 지형의 변화

This study examines the American tea culture and tea consumption patterns in the United States, analyzing development patterns of modern American tea culture, as well as trends and factors influencing tea imports and consumption. First, tea consumption in the United States in the first half of the 20th century increased at the same level or slightly higher than in the previous century despite population growth. Second, tea consumption increased dramatically due to the Prohibition Act in the 1920s and black tea particularly increased rather than green tea as more tea was imported from India, Sri Lanka, and Indonesia than from China and Japan due to the influence of the Pacific War and the Korean War in the 1940s and the 1950s respectively. Third, iced tea, which existed before the 20th century, was initially made of green tea but later changed to black tea, and as refrigeration improved, it became a representative American drink. Fourth, tea bags were invented in the previous century for economic feasibility and refine taste at first. Their quickness and convenience stimulated consumer sentiment, and when combined with CTC black tea, they gained an overwhelming advantage in the market. As stated above, American tea culture was still intact even after the 20th century, and it built its own unique tea culture that advanced from the original English tea culture, such as American tea food, informal and entertaining character, iced tea and tea bags.

Impact of High Pressure Rotorvane on CTC Black Tea Quality

Impact of High Pressure Rotorvane on CTC Black Tea Quality

CHEMOMETRICS ASSISTED VALIDATED HPLC METHOD DETECTING SEASONAL VARIANCES OF SECONDARY METABOLITES OF Camellia sinensis CONSIDERING THE ABIOTIC STRESSES

Climatic changes have great impact on the crops and agro-eco systems and such changes influences the concentration of secondary metabolites. IIT Kharagpur, India is a non-traditional tea growing zone where Tocklai Vegetative 25 variety was used as the research material. This study reports the development of a chemometrics assisted HPLC method validated as per ICH guidelines to explore the effect of seasonal variations in polyphenolics viz. catechins and methyl xanthenes like caffeine in fresh tea leaves and processed CTC black tea prepared from them. Further study was done on the variances amongst the concentration of secondary metabolites and abiotic stress factors. Good resolutions of secondary metabolites were obtained using 92% of 0.2% acetic acid and 8% of acetonitrile as the mobile phase, with a flow rate of 1 mL/ min, injection volume of 20 µl, PDA detector was set at 200-600 nm and chromatograms were recorded at 274 nm. Results of quantitative HPLC analysis have clearly shown that highest yield of catechins and caffeine were observed in fresh tea leaves plucked during spring (24.3ºC temperature and average rainfall of 34 mm) and also the processed black tea made from it, followed by tea leaves plucked during monsoon (28.8 ºC temperature and 282 mm rainfall) and processed black tea prepared from it. The lowest concentrations of secondary metabolites were found in leaves plucked during autumn (26.2 °C temperature and 132 mm rainfall) and the processed tea prepared from it. The developed quantitative HPLC method showed an inter day precision of 0.3, intraday precision of 0.2, repeatability value of 0.31, ruggedness value of 0.33 and robustness value of 0.2. Considering temperature and rainfall as abiotic stress factors, highest total polyphenolic content was obtained during spring and lowest in autumn. From our experimental findings, the fresh tea leaves of spring season and also the processed black tea prepared from it showed higher yield of catechins.

Potential application of UV-visible spectroscopy and PLS-DA method to discriminate Indonesian CTC black tea according to grade levels

In this research, UV-visible spectroscopy combined with PLS-DA method was used to discriminate Indonesian CTC black tea with two different grade levels. A total of 20 CTC black tea samples (1 gram of each samples) were collected from PT Perkebunan VIII plantation in West Java province of Indonesia. The samples consisted of two different grade levels, Broken Pekoe or BP1 (10 samples) and FNGS II (10 samples). The extraction of tea samples was performed by using hot distilled water. The spectral data of aqueous tea samples were obtained using a UV-visible spectrometer in the range of 190-1100 nm. The result of PCA showed that the tea samples can be well clustered into two groups according to grade levels using two PCs which accounted for 99% of the total variance (PC1=89% and PC2=10%). The best PLS-DA model had coefficient of determination (R2) of 0.99 with RMSEC = 0.043. The result of the PLS-DA model showed that with the moving average smoothing combined with mean normalization spectral pre-treatment samples from the two different grade levels could be 100% correctly discriminated. The results demonstrated that UV-visible spectroscopy with PLS-DA method could be successfully applied to discriminate Indonesian CTC black tea according to grade levels.

Response of Plain Black Tea Parameters, Individual Theaflavins and Yields Due to Location of Production and Clones within Lake Victoria Basin

Tea (Camellia sinensis) is a major cash crop and leading foreign exchange earner, contributing to poverty alleviation by providing employment and livelihood to many stakeholders in the producing countries. Production has increased faster than consumption causing price stagnation, especially for CTC black teas. Kenya is the third-largest tea producer and Lake Victoria Basin produces over 60% of her tea. Selection of tea cultivars in Kenya has been cantered in one location before the selected clones are introduced to other growth environments. This study evaluated if tea clones maintain their yield and plain black tea quality attributes when grown at different locations within Lake Victoria Basin. The basin produces mainly plain black teas whose quality is due to levels of polyphenolic compounds, especially green leaf flavan-3-ols that are oxidized to theaflavins and thearubigins during black tea processing. The theaflavins and thearubigins contribute to the color and brightness of black teas. The trials were done in two sites Timbilil and Kipkebe using twenty clones. All the plain tea quality parameters including individual theaflavins and yields varied (p less than 0.05) with clones, demonstrating diversity in the cultivars used. The levels of the parameters and yields also changed (p less than 0.05) with the location of production. These results demonstrated that clonal tea quality and yields vary depending on the geographical location of production. There were also significant interactions effects between the clones and location of production in the quality parameters and clones showing the extent of the changes varied from clone to clone. Indeed the relative ranking of the clones varied with location. No clone retained its relative superiority ranking at the two locations. Both the Spearman correlation coefficients (rs) and the Pearson correlation coefficients (r) between the individual parameters were positive but low and insignificant, except for theaflavin-3-gallate. These results demonstrate the need for location-specific evaluation of both new and old clones to establish clonal yield and quality potentials in new locations of cultivation.

Production of fungal pectinase enzyme through solid substrate fermentation of estate waste for improvement of enzymatic oxidation and increasing the quality of CTC tea

Enzymes, especially pectinase, plays an important role in the processing of tea that determines the quality and the color appearance of black tea. The main obstacle encountered in the application of enzymes in food processing in general, and in particular in the processing of black tea is the price of commercial enzyme that are still very expen­sive, because it is still imported. Indonesia has a high fungal diversitythat is potential as producer of commercial pectinase enzyme. To reduce the cost of production, fermentation was done using solid waste of plantation that rich of pectin content such as cocoa pod husk that has not been optimally utilized. The research aimed to develop the production technology for pectinase enzymes of fungi through solid substrate fermentation for applications in the processing of CTC black tea. Research includes the isolation and selection of local superior fungi producing enzymes pectinase, optimiza­tion of enzyme production by fungi isolates were selected through a solid substrate fermen­tation using cocoa pod husk waste, production optimization included optimization of fermen­tation time and substrate composition, enzyme extraction of fermented substrate, and appli­cation of pectinase enzyme extracts in the processing of CTC black tea and sensory test of fermented tea. The results showed that it has been obtained isolates of Aspergillus niger on Pectinase Screening Agar Medium (PSAM) which was capable of producing pectinase enzyme on growing media of mix cocoa pod husk and rice bran with additional of enrichment media. The optimum conditions of pectinase production was obtained in the composition of cacao pod husk: rice bran (80:20 w/w) plus enrichment media, the incubation time of 9 days, which produced pectinase activity of 125 U/mL. Applications of pectinase on enzymatic oxidation of CTC tea proved that it was capable of raising the quality of the tea flavor, though the tea gradedid not change.

Polyphenolic compounds and antioxidant activity of CTC black tea of North-East India

Sixty black tea samples from different agro climatic zones of northeast India were assessed for biochemical constituents that determine quality and also influence organoleptic perception. The antioxidant activities such as α,α-diphenyl-β-picrylhydrazyl (DPPH) free radical scavenging, lipid peroxidation inhibition, nitrite scavenging and super oxide scavenging, of the collected samples were analysed. Out of the four antioxidant activities, the super oxide scavenging activity was lowest and nitrite scavenging activity was highest. Theaflavin was significantly and positively correlated with nitrite scavenging and lipid peroxidation inhibition activities. Thearubigins showed a significant positive correlation only with nitrite scavenging activity. Correlations between relative antioxidant capacity index (RACI) and TF, TR and tasters’ quality were positive and significant. Tea tasters’ parameters were significantly and positively correlated with each other. Principal component analysis showed that Upper Assam, North Bank and South Bank produced better quality tea than other regions with respect to TF, TR, RACI and tasters’ quality.

Management of Cephaleuros parasiticaus Karst (Trentepohliales: Trentepohliaceae), an algal pathogen of tea plant, Camellia sinsensis (L) (O. Kuntze)

The efficacy of certain biocontrol agents were evaluated against Cephaleuros parasiticus Karst, a causal organism of red rust disease in tea plants. Spraying of systemic fungicides was found to be superior to biocontrol agents followed by algicides in controlling the disease under field condition. Dipping of shears in the solutions of fungicide, detergent or biocontrol agents failed to protect the disease spread. The study on the impact of different harvesting practices on disease development showed the highest disease incidence in continuously shear harvested fields and least in hand plucked fields. There was a reduction in disease incidence in spraying of a solution containing urea and murate of potash mixture at 1% level. The maximum green leaf yield and productivity index were recorded in biocontrol agents treated plots. Among the various group of biocontrol agents evaluated, Streptomyces sannanensis and Streptomyces griseus belong to actinomycetes was better than bacterial and fungal antagonists in terms of disease protection and increase in yield potential. Similarly, tea bush canopy architecture, physiological and biochemical parameters were also increased in plants treated with biocontrol agents. In the case of untreated control plots, the disease incidence was increased from 36% to 44.5% and the plants were found unhealthy in terms of chlorosis, stunted growth and heavy flowering with banji buds. The shoots collected from treated and untreated control plots were subjected to manufacture CTC black tea which revealed almost all the tea quality parameters were significantly improved in the treated plot over the untreated plots.

Occurrence and distribution of lipoxygenase inCamellia sinensis (L) O Kuntze and their changes during CTC black tea manufacture under southern Indian conditions

The optimal activity of tea lipoxygenase was found to be at pH 7·5 and 9·0, indicating the presence of two types of isoenzymes. Tea lipoxygenase was inhibited by cyanide and a small fraction appeared to be quite heat stable. Clonal and seasonal variations in lipoxygenase activity was significant. An increase in lipoxygenase activity was observed with leaf maturity. The lipoxygenase activity decreases with age from pruning and increases with an increase in plucking interval. The changes of lipoxygenase activity during CTC manufacture revealed that it increased with the degree of withering and upon rolling. However, a gradual decline was recorded during the fermentation and drying processes. The residual lipoxygenase activity in black tea is expected to affect its quality on storage. © 1998 Society of Chemical Industry.

In vitro studies on antifungal activity of tea (Camellia sinensis) and coffee (Coffea arabica) against wood‐rotting fungi

AbstractThe present study reports the sensitivity of ten different wood‐rotting fungi towards eight samples of tea and two samples of coffee. The tea samples included five CTC black teas, one orthodox black tea and two green teas. The different fungi tested were sensitive to different tea and coffee samples to variable levels. Green tea caused the maximum growth inhibition and it was 100% in case of Phanerochaete chrysosporium and Sporotrichum pulverulentum. Of the black tea samples, orthodox black tea was more effective inhibitor for all the fungi tested. Phlebia radiata was the most sensitive fungus to all the black tea samples except Lipton Cheers. The growth of Daldinia concentrica was least affected by all the black tea samples. The two coffee samples showed better inhibition than CTC black tea samples. The inhibitory effect of tea and coffee extracts was greatly reduced on their filtration. All the tea and coffee samples tested showed more than 50% reduction in their inhibitory activity. The inhibitory effect was completely lost in spent black tea leaves. The antifungal effect of pure caffeine was tested at different concentrations. Majority of the fungi were totally inhibited at a concentration of 0.3% whereas, D. concentrica, P. radiata and P. palustris showed complete inhibition at a concentration of 0.5 percent.

Relationship between process of withering and aroma characteristics of black tea

AbstractVolatile flavour components (VFC), caffeine, crude fibre, ash and total water soluble solids (TSS) were analysed in orthodox and CTC black teas manufactured from normal and hard withered leaves. With the increase of wither, VFC, TSS and caffeine were found to increase but not crude fibre. The withering process in black tea manufacture appears to control the development of terpenoids, improving flavour quality in brewed tea.

Flavour volatiles of Assam CTC black teas manufactured from different plucking standards and orthodox teas manufactured from different altitudes of Darjeeling

AbstractBiochemical correlations between volatile flavour constituents (VFC) of CTC bluck teas manufactured from fine and coarse plucking of Assam tea and orthodox teas fiom three different altitudes were carried out by GC‐MS. In general, fine plucking produced more monoterpenoids and less nonterpenoids than coarse plucking. The volatile flavour compounds were similar in all types of tea except that geranoic acid was detected in Darjeeling teas. The different ecosystems of Assam and Darjeeling have been found to have a pronounced impact upon aroma concentration. However, major diferences between the volatiles of teas from the different altitudes at Darjeeliny appear to be not so significant.

Effects of Nitrogenous Fertilizers on the Chemical Composition of CTC Black Tea

High rates of nitrogenous fertilizers increased the caffeine content, as well as those compounds imparting inferior and superior flavor contents. However, the flavor index, the ratio of compounds imparting superior flavor to those contributing to inferior flavor characteristics, decreased with increasing rates of nitrogenous fertilizers. Although theaflavins generally increased while thearubigins decreased with nitrogenous fertilizer rates, the relationships were quadratic. On the average, the minimum value of theaflavins was produced at about 235 kg N/ha/year.

Effects of nitrogenous fertilizers on the chemical composition of CTC black tea.

High rates of nitrogenous fertilizers increased the caffeine content, as well as those compounds imparting inferior and superior flavor contents. However, the flavor index, the ratio of compounds imparting superior flavor to those contributing to inferior flavor characteristics, decreased with increasing rates of nitrogenous fertilizers. Although theaflavins generally increased while thearubigins decreased with nitrogenous fertilizer rates, the relationships were quadratic. On the average, the minimum value of theaflavins was produced at about 235 kg N/ha/year.