• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.305-314
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• 2001

The study was conducted to investigate the effect of added green tea and black tea powder on the quality of bread during storage. Tea bread was prepared with 0.1% and 2% concentration of green tea (GT) and black tea(BT) powder. The crude fat contents of GT 2% group and BT 2% group were significantly higher than those of control group. GT l% group and BT l% group. The loaf weight of the control group was the lowest and its loaf volume was the highest. Especially, GT 2% group had the lowest loaf volume. The internal lightness value of control group was the highest. the redness value of BT 2% group and the yellowness value of GT 2% group were the highest. GT 2% group was significantly higher in hardness and gumminess and BT l% group was higher in cohesiveness and springiness. After 5 day storage, the retrogradation of GT 2% group was the highest and that of BT 2% group was the lowest among groups. After 5 day storage. pH. titratable acidity and total colony count of GT 2% group was the lowest and those of control group was the highest. The sensory score of control, GT l% and GT 2% group were evaluated higher than others. The shelf-life of tea breads were prolonged to 1~3 days by adding green tea powder and black tea powder as compared with the control group. but It must be considered the way to increase the quality of bread in loaf volume and retrogradation.

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.1
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• pp.34-42
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• 2000

The colorante from black tea infusion were applied to cotton fabric. Dyeing properties were investigated in terms of dye uptakes at various dyeing conditions and the effect of mordants on color change and colorfastness. Cotton showed low affinity to black tea colorants. Effects of mordants on dye uptake was not significant except Sn. Irrespective of mordant type, color of cotton dyed with black tea colorants was brownish and colorfastness was generally good. In order to improve dye uptake, cotton was cationized by treating with Cationon UK(tertiary ammonium salt) and chitosan. Dye uptake of cotton was remarkably increased by cationizing. Cationon UK was more effective than chitosan.

• Food Science of Animal Resources
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• v.34 no.4
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• pp.403-407
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• 2014

Changes in Maillard reaction of pidan white were monitored with $A_{294}$, fluorescence intensity, and browning intensity during pickling in the absence and presence of Chinese black tea extract (Camellia sinensis) at levels of 2% and 5% together with 0.2% $ZnCl_2$ or 0.2% $CaCl_2$ up to 3 wk, followed by ageing for another 3 wk. Browning intensity and $A_{294}$ of pidan white increased with increasing pickling/ageing, while fluorescence intensity decreased during ageing (p<0.05), irrespective of treatments. At wk 6, pidan white treated with 0.2% $ZnCl_2$ and 0.2% $CaCl_2$ showed slightly higher browning intensity, fluorescence intensity and $A_{294}$ than those treated with divalents together with Chinese black tea (p<0.05). Free amino group and sugar contents showed continuous decrease during pickling and ageing irrespective of tea and cations used. However, pidan treated without Chinese black tea extract showed significantly lower free amino group and sugar during the ageing of 6 wk (p<0.05). Thus, Chinese black tea extract had an inhibitory effect on the Maillard reaction during ageing of pidan white.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.11
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• pp.1571-1576
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• 2014

Nutritive values of green and black tea by-products and anti-nutritive activity of their tannins were evaluated in an in vitro rumen fermentation using various molecular weights of polyethylene glycols (PEG), polyvinyl pyrrolidone (PVP) and polyvinyl polypyrrolidone as tannin-binding agents. Significant improvement in gas production by addition of PEG4000, 6000 and 20000 and PVP was observed only from black tea by-product, but not from green tea by-product. All tannin binding agents increased $NH_3$-N concentration from both green and black tea by-products in the fermentation medium, and the PEG6000 and 20000 showed relatively higher improvement in the $NH_3$-N concentration. The PEG6000 and 20000 also improved in vitro organic matter digestibility and metabolizable energy contents of both tea by-products. It was concluded that high molecular PEG would be suitable to assess the suppressive activity of tannins in tea by-products by in vitro fermentation. Higher responses to gas production and $NH_3$-N concentration from black tea by-product than green tea by-product due to PEG indicate that tannins in black tea by-product could suppress rumen fermentation more strongly than that in green tea by-product.

• Journal of Life Science
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• v.6 no.1
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• pp.56-65
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• 1996

Black tea extractbsupplemented with 10% sucrose was fermented by fungus at 30$\circ$C. A pellicle thick as 7$\sim$8 mm covered entire surface of the medium and the wxtract converted to acidic beverage(abbreviated below as fermented black tea) by 14 days of fermentation. It was a kind of acetic acid fermentation depending on symbiotic microorganisms. During the fermentation strains of yeasts(Saccharomyces cerevisiae and Eeniella sp.)and bacteria(Bacillus subtilis, Kurthia zopfii, Gluconobacter oxydans and Deinicoccus sp.) were isolated from aqueous layer. Contrastly to it, a bacterial strain(Acetobacter aceti) was isolated from thick pellicle. The bacteria grew as a viscouse cluster on solid agar medium differently from usual strains of A. aceti. Fermented black tea had sweet-sour taste and sweet smell.

• KSBB Journal
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• v.16 no.2
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• pp.163-169
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• 2001

This study was undertaken to evaluate the effects of green and taste teas on the in-vitro antimicrobial activity and vacuolating toxin titer of Helicobacter pylori. Crude aqueous extracts prepared by adding 2 g of tea leaf or powder to 100 ml of boiling distilled water, and sterilized by passing through a 0.22 $mutextrm{m}$ membrane filter. Green tea, coffee, and ginger tea showed bactericidal activity on H. pylori within 3 hours. Black tea and ssangwha tea also showed bactericidal activity on H. pylori in 24 hours. Arrowroot tea show no bactericidal effect on H. pylori after 48 hours. Two fold diluted green tea and coffee decreased(1/10,000cfu) the growth of H. pylori in 24 hours, but the two fold diluted black tea, ssangwha tea, and ginger tea showed suppression effect upon of(1/10cfu) H. pylori in 24 hours. The two-fold and 10-fold diluted green tea, coffee and two-fold diluted black tea abrogated the vacuolating toxin titer of H. pylori, but the two-fold and 10-fold diluted ginger, ssangwha, ginseng, and arrowroot tea only reduced the vacuolating toxin titer of H.pylori from 1/2 to 1/8. These result suggest that green tea and coffee have effective antibacterial or bactericidal effects on H.pylori, and that they also have a neutralization effect upon the vacuolating toxin of H.pylori.

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.365-372
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• 2016

Purpose: Tea is the most frequently consumed drink worldwide, next to water. About 75% of the total world tea production includes black tea, and withering is one of the major processing steps critical for the quality of black tea. There are two types of tea withering methods: physical and chemical withering. Withering can be achieved by using tat, tunnel, drum, and trough withering systems. Of these, the trough withering system is the most commonly used. This study focuses on the different types of withering, their effect on the various quality attributes of tea, and other aspects of withering methods that affect superior quality tea. Results: During physical withering, tea shoots loose moisture content that drops from approximately 70-80% to 60-70% (wet basis). This leads to increased sap concentration in tea leaf cells, and turgid leaves become flaccid. It also prevents tea shoots from damage during maceration or rolling. During chemical withering, complex chemical compounds break down into simpler ones volatile flavor compounds, amino acids, and simple sugars are formed. Withering increases enzymatic activities as well as the concentration of caffeine. Research indicates that about 15% of chlorophyll degradation occurs during withering. It is also reported that during withering lipids break down into simpler compounds and catechin levels decrease. Improper withering can cause adverse effects on subsequent manufacturing operations, such as maceration, rolling, fermentation, drying, and tea storage. Conclusion: Freshly harvested leaves are conditioned physically and chemically for subsequent processing. There is no specified withering duration, but 14-18 h is generally considered the optimum period. Proper and even withering of tea shoots greatly depends on the standards of plucking, handling, transportation, environmental conditions, time, and temperature. Thus, to ensure consumption of high quality tea, the withering step must be monitored carefully.

• Journal of Nutrition and Health
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• v.27 no.10
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• pp.1007-1017
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• 1994

In order to investigate the effect of Korean green tea, oolong tea and black tea beverage on the antioxidative detoxification in cadmium(Cd) poisoned rat liver, male Sprague-Dawley rat weighing 143$\pm$3.2g were divided into control and experimental groups. The experimental groups were fed standard diet containing 40ppm Cd and were given distilled water(CD), 5% black tea(BT), oolong tea(OT) and green tea(GT), respectively. Tea beverages were extracted from 5G dry leaves of teas in 100ml hot distilled water by the treatment at 85$^{\circ}C$ for 3 min. Liver xanthine oxidase(XOD) activity was increased by the administration of Cd except GT group. Liver superoxide dismutase(SOD), glutathione peroxidase(GSH-px), glutathione S-transferase(GST) activities were decreased by te administration of Cd but did not decreased by the administration of green tea(in GT group). Vitamin E and reduced glutathione contents were significantly decreased in Cd administered groups. Liver lipid peroxide value in Cd administered groups were increased compared to control group, but was not increased in GT group. Serum glutamic oxaloacetic transaminase(GOT) activities in CD, OT, BT groups were higher than control, but that in GT group was similar to control group. Serum glutamic pyruvic transaminase(GPT) activity was not significantly different among various groups. It was concluded that green tea might alleviate peroxidative damage in Cd-administered rat liver by reinforcing antioxidative detoxification system.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.2
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• pp.99-104
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• 1983

Chemical changes of major tea constituents by tea manufacture were examined by the quantitative masurements of tannin, caffeine, free sugars and total amino acid. The sample used in this experiments was fresh green and black tea leaves, green tea prepared by classical panning process and black tea prepared by commercial process. The results obtained are as follows: Compared with fresh tea leaves, tannin was increased 2% in green tea and decreased 56.5% in black tea by tea manufacture. Caffeine was increased 25.9% in green tea and decreased 3.1% in black tea. Total free sugars were decreased 78.2% and 76.7% in green tea and black tea, respectively. Total amino acids were decreased 26.1% and 18.8% in green tea and black tea, respectively.

• Journal of Life Science
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• v.6 no.2
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• pp.104-110
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• 1996

The present study was conducted to elucidate the functional property of tea extract obtained from tea extracts, semi-fermented tea(oolong tea) and fermented tea(black tea). Tea extracts exhibited remarkable nitrite-scavenging actions, and the action increased with the increased of the amount of tea extracts. The nitrite-scavenging actionof tea extracts showed pH dependent, highest at pH 1.2 and lowest at pH6.0. The nitrite-scavenging rate in tea extracts/amine/nitrite systems proved to be faster than that in amine/nitrite systems. To screen the nitrite-scavenging factors, tea extracts were fractionated into water-soluble, methanol-soluble, methanol-precipitate and crude catechin fraction. Among these fractions of tea extracts, the crude catechin fraction possessed greater nitrite-scavenging action than the other fractions. The nitrite-scavenging action of tea extracts increased with the contents of total phenols and an absorbance at 280nm, nitrite-scavenging factors were supposed to be and catechins in tea polyphenol compounds.