• Korean Journal of Plant Resources
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• v.19 no.6
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• pp.670-676
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• 2006

Tea polysaccharide had high antioxidant activity and it could be used to cure diabetes. Antioxidant activity of tea poly-saccharide (TPS) from three kinds of tea (green tea, oolong tea and black tea) were compared, the result indicated that oolong tea polysaccharide (OTPS) had the highest antioxidant activity. In order to explicate the mechanism of antioxidant and hypoglycemic activity, the streptozotocin (STZ)-induced diabetes mice model (DM) was established. The influence of OTPS on blood-glucose, content of MDA and NO, and activities of GSH-PX, SOD, NOS in serum, kidney and liver were investigated. The result showed that after four weeks injection of OTPS to DM mice, the blood-glucose of three treatment group reduced by 14.5%,21.5% and 33.3%, respectively, comparing to the model control. The reduction effect of OTPS increased with the rise of dose. The activity of SOD and GSH-PX elevated significantly, while the activity of NOS decreased. The content of MDA and NO reduced significantly. The above results imply that antioxidant activity was enhanced. Comparing to XKW treatment, the effect of a dose of 300mg/(kg. bw) OTPS was much better. The research showed that the OTPS had a significant effect on reducing blood glucose, and could enhance the antioxidant activity of DM mice.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1079-1084
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• 2004

The present study was conducted to compare antioxidant activity of green teas, fermented teas and other related common teas by examining radical scavenging activity using DPPH (2,2 diphenyl l-picryl hydrazyl). Scavenging activity ($SC_{50}$/) of epigallocatechin gallate (EGCG) for 0.1 mM DPPH radical was 5.5 $\mu$M or 4.2 mg/L by weight, then catechin, 14 $\mu$M or 2.5 mg/L and vitamin C, 22 $\mu$M or 3.9 mg/L, respectively. Kyokuro tea (okro) powder of 24.2 mg/L or green tea powder of 25.2 mg/L was used to reach $SC_{50}$/ for 0.1 mM DPPH. One serving of 2 g green tea provides antioxidant activity equivalent to 109∼147 mg EGCG, 145∼185 mg catechin or 131∼168 mg vitamin C. Teas from the first harvest had the highest radical scavenging activity when compared with later harvest green teas grown in the same region, but there is virtually no difference by the harvest time. A Chinese green tea, Dragon well had the highest antioxidant activity among other green teas tested providing antioxidant capacity equivalent to 168 mg EGCG or 188 mg vitamin C per 2 g serving, but partially fermented Chinese teas had much lower antioxidant activity than any green tea tested. Black tea which is fully fermented showed as strong antioxidant activity as green teas (76.3 mg vs 86.7∼67.6 mg per tea bag). One tea bag of green teas from market provided antioxidant capacity equivalent to 52∼86 mg EGCG, 70∼105 mg catechin or 63-96 mg vitamin C. Teas made of persimmon leaf, pine needle, mulberry leaf had comparatively low anti-oxidant activity equivalent to 2.5∼4.8 mg EGCG or 15∼21 mg vitamin C per teabag. The third brewed green tea still had enough antioxidant activity, while tea from tea bag brewed for 3 min or 5 min did not have any difference in their antioxidant activity. More systemic studies are needed to clarify the relationship between tea catechins and antioxidant capacity focusing on how growing, harvest time, fermentation and other processes can influence on this.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.12-18
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• 2001

The water-soluble extracts of plants used as tea materials were investigated for their antioxidant activities and active components(total phenolics, ascorbate and selenium). Antioxidant activities of the plant extracts were determined by measuring the changes in both peroxide values(POV method) during storage(36 day, $55^{\circ}C$) and conductivity of soybean oil at $110^{\circ}C$(Rancimat method). Soybean oil without any additive was used as a control. Soybean oil treated with 0.02% BHT was used as a positive control. The test samples were prepared by mixing the plant extracts with soybean oil in 0.02% concentration by weight. The water-soluble extracts of lycii fructus(23 d), oolong tea(23 d), orange peel(23 d), citron(22 d), and apricot(22 d) showed longer induction periods, compared to control(21 d) and BHT(21 d) by POV method. Also water-soluble extracts of oolong tea(12 h), instant coffee(11 h), citron(10 h), cinnamomi cortex(10 h), schizandrae fructus(10 h), lycii fructus(10 h) and apricot(10 h) demonstrated longer induction periods, compared to control(8 h) and BHT(8 h) by Rancimat method. The contents of total phenolic compounds were observed to be high in water-soluble extracts of oolong tea, green tea, black tea, coffee, cinnamomi cortex, and cassiae semen. Ascorbate contents were found to be high in coffee, eucommiae cortex, black tea, ganoderma, cinnamomi cortex, persimmon leaf, chicory, green tea and oolong tea extracts. The selenium contents were not detected in all the extracts. The antioxidative effects of some plant extacts were seemed to be the combined effects of various antioxidant components such as phenolics and ascorbate.

• Culinary science and hospitality research
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• v.12 no.4 s.31
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• pp.213-224
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• 2006

This study was to investigate the factors affecting drinking Korean traditional beverages and the drinking habits of college students in Seoul. The research was carried out by asking them to drink 10 kinds of traditional drinks. They were composed of 45.5% of boys and 54.5% of girls who were $18\sim21$ years old, studying food related science (63.9%), and mostly (86.6%) living in a nuclear family in collective residents (60.4%) like an apartment. The number of students whose family's monthly incomes were over 3 million won was the largest as 37.1%. Their mothers were housewives (58.4%) mostly aged $46\sim50$ as 47.0%. In the research on the preference of students for the traditional drinks, most of them, 78.7%, showed their liking for the drinks because of their good taste (61.%). The number of students who answered they got the drinks by homemaking was the largest as 39.6%. Most of them, 66.3%, preferred fruit drinks, 19.8% soda drinks, 11.4% traditional drinks and 2.5% functional drinks. 31.2% of the drinks mostly taken at home was green tea, followed by sweet rice drink, Shik-hae. Among the drinks coming into the market, sweet rice drink was preferred in general as 25.7%, and the next was green tea 16.8%, ume drink (Maesil tea) 14.9%, rice tea 13.9%, fruit punch (Sujeonggwa) 11.4%, black tea 7.9%, honey tea 4.5%, ginseng tea 2.5% and jujube tea 2.5%. In the research on 'whether the students had experience preparing the traditional drinks or not', many of them, 62.4%, answered "No". And in the questionnaire asking on 'whether they liked to receive a training on making traditional drinks or not', 87.6% of them showed their wish to get the training. In the question on the reason why the students did not like to take the training on traditional drinks, the number of students who answered that it was complicated and hard to prepare was the largest as 53.0%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.12
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• pp.1838-1842
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• 2016

Kombucha (K) is a fermented beverage made from black tea by symbiotic micro-organisms of bacteria and yeasts. To enhance bio-activities of K, we produced citrus/green tea Kombucha (CK) by adding extracts of citrus peel and green tea obtained from Jeju Island. ORAC assays showed that anti-oxidative capacity of CK increased by approximately 3-folds compared to K. We examined anti-cancer properties of extracts from citrus peel and/or green tea using 5637 human bladder cancer cells and B16F10 murine melanoma cells. Proliferation of B16F10 cells was markedly inhibited at concentrations higher than $10{\mu}L/mL$. At a concentration of $20{\mu}L/mL$, anti-cancer activities of extracts were in the order of citrus peel< green tea< combination of both. Interestingly, a combination of both extracts showed a synergistic effect on inhibition of growth of cancer cells. CK fermented with citrus peel and green tea extracts showed enhanced anti-cancer activity compared to K. Cytotoxicity of CK on RAW 264.7 murine macrophages was negligible up to $100{\mu}L/mL$. Taken together, these results indicate that citrus Kombucha is safe to be developed as a functional beverage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.9
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• pp.1134-1139
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• 2007

This study was conducted to investigate the effects of four kinds of tea (Camellia sinensis) extracts on the antioxidant defense systems as well as the activities of alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) in ethanol administered ICR mice. According to the results, treatment with puerh tea significantly increased the superoxide dismutase activity and glutathion reductase activity in liver. In addition, the group treated with oolong tea exhibited higher superoxide dismutase activity and glutathion reductase activity in serum than those of puerh tea, green tea and black tea treated groups. The oolong tea and puerh tea also reduced malondealdehyde contents in both liver and serum. These results suggested that puerh tea and oolong tea were the most effective against alcohol-induced oxidative damage among the Camellia sinensis teas. On the other hand, in the measurement of alcohol break-down enzyme activities, the group treated with green tea exhibited the highest hepatic ADH and ALDH activities, suggesting that the group treated with green tea might be useful for alcohol down-regulation.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.45-45
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• 2001

Heterocyclic aromatic amines (HCAs) are established genotoxic human cancer risks, that display their activity also in a number of animal models and in vitro. They are formed during the trying or broiling of creatinine-containing foods, mainly fish or meat. We established that mixing soy protein with ground meat blocks the formation of HCAs. we also observed that coating the surface of meat with polyphenols green or from black tea gives a dose - related reduction of the formation of HCAs.(omitted)

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.3
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• pp.367-372
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• 2008

Yukwa were added with non-fermented tea (Bucho-cha and Okro-cha), semi-fermented tea (Ooreung-cha), and fermented tea (black tea) to investigate the effect of different kinds of tea powder on quality characteristics of Yukwa during storage. Yukwa samples were used for analysis such as crude lipid, moisture, texture, antioxidative property (TBA value), and sensory test. There were no significant differences on crude lipid, moisture, and texture analysis. Green tea powder treatment showed strong antioxidant activity. In particular, antioxidant property of non-fermented tea exhibited a higher antioxidative effect than that of the other samples. Sensory evaluation showed that sensory scores of samples added with non-fermented tea were significantly higher than the other samples, indicating that the addition with 0.1% of non-fermented tea powder could contribute to the improvement of quality and shelf-life of Yukwa during storage.

• 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)

• Applied Biological Chemistry
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• v.35 no.4
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• pp.276-280
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• 1992

Quantutative analysis of catechins by HPLC was studied. When the mobile phase was switched from the conventional(AOAC) Methanol, Acetonitril and Acetic acid solution in $H_2O$ to 0.06% Phosphate solution with Acetonitrile, N,N-Dimethyl formamide, and Ethyl acetate, retention time could be reduced from 45 min to 28 min, especially, we obtained sharper chromatogram of the compounds, either (-)EGCG or (-)ECG, which resulted in minimization of analytical erros. CVs of retention time $(0.32{\sim}3.97%)$ and peak area $(1.61{\sim}7.01%)$ indicated that the data were more reliable. Content of catechins in commerical teas analyzed by the method was $120.3{\sim}153.7\;mg/g$ in green teas which was about 4 times that in black tea.