• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.740-744
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• 1994

This study was undertaken to prove the suppressing effect of green tea on the intestinal absorption of heavy metals using in vitro membrane filtration system. From drinking water contaminated with 10 and 100 times level of water quality standard for heavy metals, the removal ratio of lead (Pb) was $50{\sim}70%$ by green and black teas, and $30{\sim}40%$ by roasted barley tea. The removal ratio of cadmium (Cd) was $30{\sim}40%$ by green tea and black teas, and $10{\sim}20%$ by roasted barley tea. The removal effect from drinking water contaminated with both lead and cadmium was lower than that from water contaminated singly with lead or cadmium. It appears that tea components and filter membrane compete toward the adsorption of two heavy metals. Among the extraction conditions of raw tea materials at $70^{\circ}C$, 2 minutes and $95^{\circ}C$ , 10 minutes, the removal ratios of heavy metals were similar.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.100-106
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• 1999

Use of chemical preservative for controlling harmful microorganisms in food products has been debated due to public concerns about food quality because of perceived toxic and carcinogenic potential. Thus, use of non toxic natural antimicrobial agents has become essential. This study was investigated to determine the antimicrobial activity of water or ethanol extract of commercially available tea, and of solvent fractionated ethanol extracts obtained from steamed green tea. Both of water and ethanol extracts of green tea(steamed or roasted), oolong tea and black tea exhibited strong antimicrobial activity against gram positive and negative bacteria, but not effective against yeast and mold. Also, antimicrobial activity of ethanol extract of 4 different kinds of tea was stronger than that of water extract. Among 4 different tea, ethanol extract of steamed green tea was further fractionated. One thousand g/disk buthanol extract had the strongest antimicrobial activity against bacteria and mold. The concentration of the antimicrobial activity of buthanol extract in tested microorganisms ranged from 125~1000 g/disk except for Rhizopus javanicus. Antimicrobial activity of buthanol extract of steamed green tea was not destroyed by heating at 100oC for 60 min and at 121oC for 15 min, which is very stable over heat treatment. The inhibitory effect of the buthanol extract on the growth of Listeria monocytogenes and Staphylococcus aureus was investigated. Growth of both strains was started in the presence of 250 and 500 g/ml after 12 and 24 hour respectively, whereas complete inactivation of both strains was occurred in the presence of 1000 g/ml.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.160-168
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• 1995

Desmutagenicities against 2-amino-1-methyl-6-phenylimidazo[4, 5-b] pyridine(PhIP) and 2-amino-3, 8-dimethylimidazo[4, 5-f]quinoxaline(MelQx) of tea extracts (steamed green tea, roasted green tea, oolong tea and black tea) were investigated. All the fractions obtained from tea extracts showed strong desmutagenic activity against PhIP and MeIQx toward S. typhimurium TA 98 in the presence of the S-9 mix. The crude catechin fraction exhibited the strongest desmutagenic activity. Among these tea extracts, black tea especially exhibited the strongest desmutagenic activity and the activity was 70.9~91.0% against PhIP and 92.2~98.8% against MelQx at a concentration(0.5~1.0mg/plate) for drinking. The activity of authentic catechins of (-)-EGC, (-)-EGCg, (-)-ECg and (-)-EC were 79.5%, 60.2%, 46.1% and 43.5% against PhIP, and were 52.3%, 11.6%, 8.2% and 22.1% against MelQx by addition of 1.0mg/plate, respectively. The desmutagenic activity was supposedly due to the (-)-EGCg, (-)-EGC and (-)-EC in tea polyphenols, and the browning materials. The desmutagenicity was stronger when mutagens were preincubated with S-9 mix after reaciton with black tea extracts than when preincubated with them after reaction with S-9 mix. The desmutagenicity of tea extracts was rather expressed by reacting directly with mutagens than by deactivating the activated forms of mutagens.

• Journal of the Korean Home Economics Association
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• v.23 no.2
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• pp.29-36
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• 1985

This experiment was conducted to investigate changes of the components in steamed and roasted green tea after 10 min, 20 min and 30 min of heat treatment of heat treatment at $110^{\circ}C$. Vitamin C and tannin were determined by spetrophotometry. Total nitrogen, water-soluble nitrogen and water-soluble non protein nitrogen were determined by Kjeldahl analysis system. Aromas were identified by gas chromatography. After heat treatment, contents of most compounds decreased. Tannin and caffeine decreased a little bit, while vitamin C decreased considerably. There were both decreases and increases in aromas. Aromas which increased were geraniol, trans-2-hexenol, linalool, $\alpha$-ionone and $\beta$-ionone. From these results, it was concluded that the highest quality of green tea was one steam- treated for 10 min at $110^{\circ}C$.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.3
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• pp.478-483
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• 1996

The aroma components of Korean green tea in the south western part of Mt. Chiri prepared by the traditional method from native variety were analyzed using GC and GC-MS. The patterns on GC chromatograms of the three samples from the flushes plucked in early spring were similar, though they are prepared by different producers in the area of Hadong-kun, Kyung sang nam-do. A total of 51 aroma compounds were identified in all samples. Main component in the aroma compounds of these teas were geraniol, benzyl alcohol, 2-phenylethanol, $\beta$-ionone, benzyl cyanide and linalool oxides. The aroma components of green teas manufactured by the different plucking periods were also compared. The amounts of geraniol, typical rose floral aroma were particularly decreased in the final plucking period. The amounts of pyrazines and furfuryl alcohol, typical roasted aroma and nutty aroma were slightly increased in later plucking period.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10b
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• pp.34-35
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• 2003

Before making of tea, the number of leaf, plant height and node length in young shoot were 5.2, 14.9cm and 1,9cm respectively. These contents caused problems in leaf rolling and uniformity. No significant difference in quality and comoposition of roasted and steamed were observed, external shape and internal quality, however, were good from 1st to 3rd leaf. Chemical nutrition consists of leaf position, Total nitrogen content of terminal leaf was 4.88%, total free amino acid 21.12%, and caffein 3%. Vitamin C content was increased with increasing of leaf age. Making of roasted tea was required long time because camellia leaf was very hard and smoothly. Products had lower water color, perfume and taste. Internal quality of steamed tea was good in water color and taste. The contents of total nitrogen, total free amino acid, catechin, caffeine and vitamin C were 4.24%, 1.01, 17.7%, 2.6% and 75.7mg/ml.(중략)

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.102-102
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• 2003

The present study has been undertaken to characterize availability of camellia(Camellia japonica L.) as a medicinal plant with antineoplastic and chemosensitizing activities. The crude extracts from fresn camellia flower, young leaves and nutraceutical tea of camellia leaf and flower buds were evaluated on their potential activities against various human cancer cells and multidrug resistance to cancer cells in vitro. The range of cytotoxicity displayed from 120$\mu\textrm{g}$/mL to 200$\mu\textrm{g}$/mL. Catemix 1(CT-1) mixed with camellia and green tea showed high toxicity(respectively IC$\sub$50/=l16$\mu\textrm{g}$/mL, 129$\mu\textrm{g}$/mL) against AML-2/WT, acute myelogenous leukemia cell and MCF-7, brest adenocarcinoma pleual effusion cell. Generally camellia tea mixed with green tea showed higher cytotoxicity than the other camellia teas mixed with some herbs(CH). Methanol extract of steamed camellia tea and roasted camellia tea had a chemosensitizing effect to reverse Pgp-mediated MDR. In addition, camellia flower tea of insignificant cytotoxicity, chemosensitizing effect were increased remarkably chemosensitizing effect in mixed flower tea with some herbs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.3
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• pp.301-304
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• 1985

Changes of free amino acids and free sugars in steamed and roasted green tea were determined after heat treatment at $110^{\circ}C$. Sixteen kinds of free amino acids and four kinds of free sugar were analyzed by HPLC. Free amino acids isolated were aspartic acid, threonine, serine, glutamic acid, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, histidine, lysine and arginine. Free sugars were sucrose, glucose, fructose, and raffinose. After the heat treatment, free amino acids and free sugars were decreased considerably.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10b
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• pp.48-49
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• 2003

This project was conducted to development several camellia tea mixed herb teas having any physiological effects. Leaves of tea tree contain many compounds, such as polysaccharides, volatile oils, vitamins, minerals, purines, alkaloids(eg. caffeine) and polyphenols(catechins and flavonoids). Although all three tea types(green, oolonr and black) have antibacterial and free radical capturing(antioxidizing) activities, the efficacy decreases substantially the darker the variety of tea is. This is due to lower contents of anti-oxidizing polyphenols remaining in the leaves. Unlike tea tree(Camellia sinensis), the biochemical features and effects of camellia(Camellia japonica) are not well known. Fresh mature leaf of sasanqua camellia(C. sasanqua), roasted young leaf tea(C. japonica) and fresh mature leaf and bark of camellia had high antibacterial activity against P. vulgaris and B. subtilis. In antifungal activity bioassay, young leaf roasted teas of camellia and sasanqua camellia had high activity against C. albicans and T. beigelil. Plant extracts from Camelia japonica had higher inhibitory activity against fungi than against bacteria. In cytotoxic effect against human acute myelogenous leukaemia cell extracts including fresh leaf(200$\mu\textrm{g}$/m1), bark(230$\mu\textrm{g}$/ml) and flower tea (320$\mu\textrm{g}$/m1)inhibited growth of AML cells.(중략)