• Journal of the East Asian Society of Dietary Life
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• v.18 no.3
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• pp.391-396
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• 2008

This study was carried out to help restore and spread broaden the consumption of Chungtaejeon, a our traditional tea, Chungtaejeon in Korea, and as well as to gather the basic data on Chutaejeon tea. We have also compared the various ingredients components and physiological activities of Chungtaejeon tea extracts with that of green tea extracts. According to the results, the total phenol contents in of the Chungtaejeon and green tea extracts were 90.56 and 98.70 mg/100 mL, respectively, and their tannin contents levels in Chungtaejeon and green tea extracts were 214.14 mg/100 mL and 259.60 mg/100 mL, respectively, showing a difference in content. The catechin contents of the Chetaejeon and green tea extracts were in the order of EGC($15.80{\sim}16.50\;mg/100mL$), EGCG($10.40{\sim}10.60\;mg/100 mL$), and ECG($9.55{\sim}9.88\;mg/100 mL$), however, with the exception of EC(7.86 mg/100 mL) in the green tea extracts, there were not significant differences between that in them Chetaejeon and green tea extracts. Quercetin was the main flavonoid ingredient component in those both the Chungtaejeon and green tea extracts was quercetin, at levels of 0.08 mg/100 mL and 0.06 mg/100 mL and its contents in Chungtaejeon and green tea extracts were 0.08 mg/100 mL and 0.06 mg/100 mL, respectively. The primary amino acid in both tea extracts was theanine main amino acid at levels of, theanine contents were most increased in 8.02 mg/100mL and 10.80 mg/100 mL, respectively, Chungtaejeon tea extracts by 8.02 mg/100 mL and green tea extracts by 10.80 mg/100 mL. And the arginine contents of the Chungtaejeon and green tea extracts in Chungtaejeon and green tea extracts were 1.78 mg/100 mL and 1.86 mg/100 mL, respectively. In terms of mineral composition, potassium content was highest contents in the Chungtaejeon and green tea extracts by 19.80 and 18.04 mg/100 mL, respectively. Finally, the Chungtaejeon tea extracts offered the greatest anti-oxidation and ACE inhibition activities were most increased in the Chungtaejeon tea extracts, and the green tea extracts showed the highest level of nitrite radical scavenging activity at 90% was extremely much increased in the green tea extracts by 90%.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.2
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• pp.243-249
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• 2011

This study investigated the physiological and antioxidant activities of green, oolong, and black tea extracts. The crude catechin extract yields of green, oolong, and black tea were 4.9%, 3.4%, and 2.5%, respectively. Total phenol contents of green, oolong, and black tea were 40.9%, 43.0%, and 38.5%, respectively. The order of the electron donating abilities of green, oolong and black tea were green tea>oolong tea>black tea extracts. The SOD-like activities of green, oolong and black tea extracts at 5,000 ppm were 21.2%, 17.5% and 13.9%, respectively. The nitrite-scavenging abilities of green, oolong and black tea extracts were higher than that of ascorbic acid (p<0.05). Antioxidant activities in soybean oil substrates at 500 ppm were in the order of green tea>oolong tea>black tea${\geq}$BHT (200 ppm). Therefore these results showed that the physiological and antioxidant activities of green tea were better than those of oolong and black tea.

• Journal of the Korean Society of Food Culture
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• v.20 no.6
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• pp.675-682
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• 2005

This study was aimed to determine microbiological quality by adding green tea extracts to chicken meat salad. For this study, Chicken meat salad were prepared with two production method. (method 1: addition of green tea extracts to boiling phase, method 2: addition of green tea extracts to salad dressing) Microbiological effects of green tea extracts were assessed during production process by measuring process time, temperature, pH and Aw and determining total plate counts and coliforms. Effects of green tea extracts on total plate counts and coliforms were observed during holding at 3, 10, $25{\pm}1^{\circ}C$ for 12 hours. Green tea extracts improved the microbiological quality and showed antibacterial properties when they are added to chicken meat salad.

• Food Science and Preservation
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• v.8 no.2
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• pp.206-212
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• 2001

Water extract of green tea(GTW) and 70% ethanol extract of green tea(GTE) were prepared for the test of antibacterial activity. The sensitivity of Staphylococcus aureus and Salmonella typhimurium to the green tea extracts in various pH of culture broth was tested. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts was adjusted to pH 5.0∼7.0 and inoculated with 10$\^$5/∼10$\^$6/ cells/ml of each bacteria. The plate counting method and clear zone test were used to determine inhibitory effect of green tea extracts. Green tea extracts completely inhibited the growth of S. aureus at 0.5% level and bactercidal at 0.5∼1.0% level of GTW and GTE at pH 5.0∼7.0. Green tea extracts were bactercidal to S. typhimurium at 1.5∼2.0% level of GTW and 1.0∼2.0% level of GTE at pH 7.0. Sal. typhimurium was more resistant than S. aureus. in same concentration of green tea extracts at same pH. The resistance of S. aureus and Sal. typhimurium was increased with decreasing pH of culture broth. The morphology of S. aureus cells treated with green tea extracts showed damage of cell wall and cytoplasmic membrane. Severely damaged cells of S. aureus lost electron dense material and cytoplasm. Green tea extracts stimulated autolysis and cell death of S. aureus. This result suggests that green tea extracts can be used as an effective natural antibacterial agent in food.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.293-298
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• 1995

Antimicrobial effect of tea extracts from green tea(steamed, roasted), oolong tea and black tea was investigated. Minimal inhibitory concentration(MIC) of tea extraxcts against 9 well known strains of foodborne pathogenic bacteria such as the Gram positive and Gram negative bacteria was determined at 37$^{\circ}C$. Significant antimicrobial activity was observed in the steamed green tea and the roasted green tea of the water-soluble fraciton, and the steamed green tea of the methanol-soluble fraction, and the steamed green tea, roasted green tea and the oolong tea of the crude catechin fraction. The MIC of these extracts against B. subtillis were 700$\mu\textrm{g}$/ml, 500$\mu\textrm{g}$/ml and 120 $\mu\textrm{g}$/ml, respectively. The crude catechin fraction possessed greater antimicrobial activity than did the other fractions. Among tea extracts, extracts of steamed green tea, roasted green tea and oolong tea showed higher antimicrobial activity than them of black tea. The MIC of the crude catechin fraction obtained from tea extracts against Gram-positive bacteria such as M. Iuteus, B. subtillis and S. mutans were 30~50$\mu\textrm{g}$/ml, 120~240$\mu\textrm{g}$/ml and 120~180$\mu\textrm{g}$/ml, and against Gram-negative bacteri such as e. aerogenes and V. parahaemolyticus were 50~60$\mu\textrm{g}$/ml and 60~70$\mu\textrm{g}$/ml in the broth medium, respectively. Especially, the MIC to Streptococcus mutans which has known as a causative bacteria of a decayed tooth were 120$\mu\textrm{g}$/ml, 140$\mu\textrm{g}$/ml, 180$\mu\textrm{g}$/ml and above 1,000$\mu\textrm{g}$/ml in steamed green tea, roasted green tea, oolong tea and black tea, respectively. Tea extracts had strong growth inhibition activity against foodborne pathogenic and dental bacteria.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.1
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• pp.57-64
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• 2005

The effects of water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower on serum lipid concentrations were evaluated in rats. Forty-eight male Sprague-Dawley rats weighing l00±l0 g were divided into six groups and fed high fat diets for six weeks. Experimental groups were administered with following diets; Control diet, animal, plant high fat diet and control and high fat diets with 2% water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower. Tissue weights of liver, lung, stomach, heart, kidney and spleen of high fat diet exposed rats were reduced by water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups. The concentrations of serum triglyceride in rats fed the water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower were lower than those in other groups. The concentrations of total cholesterol in water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower group were lower than those in high fat diet groups. The concentrations of HDL-cholesterol in serum of the water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups were significantly higher than those of other groups. The levels of LDL-cholesterol in serum of the water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups were tended to be lower than those of other groups. GPT and GOT activities were decreased in water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups and than in the high fat group. LDH activity was lower in the water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups than in the high fat group. These results suggest that water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups may reduce elevated levels of serum lipid concentrations in rats fed high fat diets.

• Korean journal of food and cookery science
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• v.21 no.4 s.88
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• pp.466-474
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• 2005

This study aimed to determine the microbiological quality obtained by adding green tea extracts to prepare cook-chill foods. For this study, chicken meat salad was blended with green tea extracts at concentrations of 0, 2 and $3\%$ and prepared for a cook-chill system. The microbiological effects of green tea extracts were assessed during the production process by measuring process time, temperature, pH and Aw and by determining total plate counts and coliforms. The effects of green tea extracts on total plate counts and coliforms were observed during cold storage at $3^{\circ}C$ for five days. Green tea extracts improved the microbiological quality and showed antibacterial properties when added to chicken meat salad prepared in a cook-chill production system. The use of green tea extracts should be further explored as a means of enhancing freshness and quality in cook-chill foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.2
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• pp.287-292
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• 1994

This paper was investigated to elucidate the nitrite-scavenging action as one of biological actions of green tea extracts. Green tea extracts exhibited remarkable nitrite-scavenging action. Among the green tea extracts, steamed green tea showed higher nitrite-scavenging action than roasted green tea. Nitrite-savenging actions of gren tea extracts were hardly influenced until three times extraction with hot water. Furthermore , the nitirte-scavenging action of green tea extracts showed ph dependent , highest at pH 1.2 and lowest at pH 6.0. The nitrite -scavenging rate in sample extracts /amine /nitrite systems exhibited faster than that in amine/nitrite systems. In order to screen the nitirte-scavenging factors, samples extracts were fractionated with methanol. in both samples, methanol-soluble fractions possessed greater nitrite-scavenging action than methanol-insoluble fractions .The nitrite-scavenging action of methanol-soluble fractions increased with proportion to absorbance at 420nm and at 280nm, while that of green tea extracts increased with the contents of total phenols and absorbance at 280nm.

• The Korean Journal of Food And Nutrition
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• v.13 no.1
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• pp.36-44
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• 2000

Survival of pathogenic bacteris(S. aureus, L. monocytogenes, E. coli and S. typhimurium) in tryptic soy broth containing green tea water extract(GTW), green tea ethanol extract(GTE), potassium sorbate (PS) and sodium benzoate(SB) stored at various pH was evaluated. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts and preservatives adjusted to pH 5.5, 6.0, 6.5 and 7.0 was inoculated approximately 105 CFU/ml of pathogenic bacteria and incubated at 35$^{\circ}C$ for 24∼48 hours. Survival of bacteria was determined by viable cell counts of bacterial culture at each pH. Minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) of green tea extracts and preservatives against pathogenic bacteria were derived from survival curves of each bacteria. Antibacterial activities of green tea extracts increased with increasing pH but those of preservatives decreased with increrasing pH. S. aureus was the most sensitive strain to GTW and GTE but the most resistant to PS and SB. The MICs of green tea extracts to S. aureus were 0.52∼0.98% at pH 5.5∼6.0 and non inhibitory at pH 7.0. S. typhimurium was the most resistant to green tea extracts while the most sensitive to SB. The MICs of green tea extracts to S. typhimurium were 0.46∼1.62% at pH 5.5∼6.0 and 2% of PS was bactericidal at pH 5.5. 1.0∼2.0% of GTE were bactericidal to all strains tested except L. m9oncytogenes at pH 7.0. GTE was most efficient at inactivating pathogenic bacteria, generally followed by GTW, PS and SB.

• Journal of Nutrition and Health
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• v.34 no.5
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• pp.499-512
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• 2001

This study was performed to investigate effects of dried leaf powders, water, 75% and 95% ethanol extracts of persimmon leaf and green tea on lipid metabolism, lipid peroxidation and antioxidative enzyme activity in 12-month-old rats. Fifty-four male Sprague-Dawley rats weighing 542$\pm$4.5g were blocked into groups according to their body weight and were raised for four weeks with the diets containing 5%(w/w) dried leaf powders of persimmon(Diospyros kaki Thunb) and green tea(Camellia Sinensis O. Ktze), water or 75% and 95% ethanol extracts from same amount of each dried tea powder. Food intake was not significantly different among all groups, but weight gain of green tea powder group was significantly lower than that of control group. Plasma and liver lipid levels of all the tea diet groups were lower than those of control group. Especially, 75% ethanol extract of persimmon leaf decreased total lipid and triglyceride concentrations in plasma and 95% ethanol extract of persimmon leaf decreased liver total lipid level. However, there was no difference between 75% ethanol extracts groups and 95% ethanol extracts groups in lipid metabolism. Superoxide dismutase(SOD) and catalase activities in erythrocyte were remarkably increased by all the green tea diets. SOD, catalase and glutathione peroxidase activities in liver were increased by the feeding of ethanol extracts from green tea and persimmon leaf powder. Liver xanthine oxidase activity was not different among all groups. Plasma Thiobarbirutic acid reactive substance(TBARS) concentrations of all the green tea diet groups were significantly low. It was thought that high flavonoids in green tea inhibited plasma lipid peroxidation by promoting SOD, catalase activities in erythrocyte. 95% ethanol extract of persimmon leaf also inhibited plasma lipid peroxidation by high vitamin E and beta-carotene. Persimmon leaf powder decreased liver TBARS concentration by vitamin E, betacarotene and vitamin C and by increasing activities of antioxidative enzymes with flavonoids. In conclusion, dried leaf powders, water, 75% and 95% ethanol extracts of persimmon leaf and green tea were effective in lowering lipid levels and inhibiting lipid peroxidation in 12-month-old rats. Above all, ethanol extracts of persimmon leaf decreased plasma and liver lipid levels and persimmon leaf powder effectively inhibited liver lipid peroxidation. Extracts of green tea leaf inhibited plasma lipid peroxidation. In lowering lipid levels and inhibiting lipid peroxidation, ethanol extracts were more effective than water extracts, but there was no difference between 75% ethanol extracts and 95% ethanol extracts in lipid metabolism. (Korean J Nutrition 34(5) : 499~512, 2001)