• Preventive Nutrition and Food Science
• /
• v.4 no.2
• /
• pp.92-96
• /
• 1999

The effects of aqueous extracts from Korean commercial teas on excessive free radicals were examined utilizing spin trapping, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical and lipid peroxidation. A potent scavenging effect of green tea and oriental senna tea was dound using sipin trapping. The most effective teasagainst the DPPH radical was green tea, followed inorder by pine leak tea, Chinese gutta percha tea and orietnal senna tea. Similar to the effects of DPPH radical , green tea, pine leaf tea, Chinese gutta percha tea and oriential senna tea had an inhibitory effect on lipid peroxidation. These findings predict that Korean tea is a promising material for scavenging free radicals, and for curing diseases related to free-radical reactions.

• The Korean Journal of Pesticide Science
• /
• v.15 no.1
• /
• pp.28-35
• /
• 2011

The investigation of 218 residual pesticides for 19 types of tea (persimmon leaf tea, chrysanthemum tea, green tea, lavender tea, rosemary tea, dandelion leaf tea, puer tea, mulberry leaf tea, hydrangea leaf tea, jasmine tea, nuomixiang tea, buckwheat tea, mugwort tea, lotus leaf tea, oolong tea, longjing tea, rose tea, tiehkwanyin tea and huoguo tea) obtained from markets in Ansan and Suwon was carried out to assess the risk for residual pesticides in tea. The detection rate was 23.1 % (19 samples of total 65 tea samples) and the detected pesticides were 15 pesticides, such as bifenthrin, bromopropylate, chlorpyrifos, cyhalothrin, cypermethrin, chlorfenapyr, dicofol, endosulfan, fenpropathrin, fludioxonil, fenvalerate, iprobenfos, isoprothiolane, tetradifon and triazophos. The range of concentrations for the detected residual pesticides was 0.01 to 1.24 mg/kg which showed below their maximum residue limits (MRL), but the residual concentration of bifenthrin in a puer tea showed above the legal limit of 0.3 mg/kg. The result of risk assessment of residual pesticides for the detected 15 samples showed that EDI (estimated daily intake) of the pesticides detected ranged 0.0001~0.0844% of their ADI (acceptable daily intake).

• The Korean Journal of Food And Nutrition
• /
• v.15 no.4
• /
• pp.377-381
• /
• 2002

The antioxidative effect of tea extracts from green tea, oolong tea and black tea was investigated. The extraction yields of crude catechin were green tea 5.4%, oolong tea 3.5%, and black tea 2.5%. Green tea, oolong tea and black tea of crude catechin showed antioxident activity at concentrations of 200ppm, and the oolong tea showed highest antioxidant effect. The browning intensities(at 420 nm) of green, oolong and black tea were 0.140, 0.582 and 0.915, respectively and green tea showed highest hydrogen donating ability(HDA) and than followed by oolong or black tea. Also, when the crude catechin(100 ppm) was used in combination with ${\alpha}$-tocopherol(50 ppm) and ascorbyl palmitate(50 ppm), the crude cathechin showed very strong synergistic effect, comparable to that of crude catechin(200 ppm).

• Korean journal of food and cookery science
• /
• v.23 no.2 s.98
• /
• pp.165-172
• /
• 2007

This study was conducted to investigate the antioxidant amounts and properties of barley leaf tea and green tea at under various leaching conditions. The leaching temperatures and times of the distilled water were 50, 70 and $90^{\circ}$C for 1, 3 and 5 min, respectively. The levels of crude fat and ash in the barley leaf tea were higher than those in green tea. Brown color intensity and flavonoid absorbance increased with leaching temperature. The highest vitamin C levels and water-soluble phenol resulted at $90^{\circ}$C for 3 min. The DPPH radical scavenging activities of the barley leaf tea and of green tea were 11.06 and 50.56%, respectively, compared to 2.9% for L-ascorbic acid (150 ppm). The nitrite scavenging activities of barley leaf tea and green tea were 95.11 and 74.88%, respectively. The SOD-like activities of barley leaf tea, green tea, and L-ascorbic acid (150 ppm) were 12.99, 8.33, and 12.75%, respectively. The antioxidant effect of green tea was higher than that of barley leaf tea and lastly, the SOD-like activity of barley leaf tea was as high as that of green tea.

• Journal of Society of Preventive Korean Medicine
• /
• v.21 no.2
• /
• pp.95-103
• /
• 2017

Objectives : The aim of this study is to analyze the news contents of Korean style medicinal tea and investigate how it is portrayed in the consumer market. Methods : Total of 355 articles are selected by inputting "Korean style medicinal tea" and analyzed; 108 articles for 2013, 107 articles for 2014, 140 articles for 2015. Results : 175 different tea were found from Jan. $1^{st}$ 2013 to Dec. $31^{st}$ 2015, with ginger tea the most frequently covered for 68 times. Among 175 tea, 117 had one ingredient and 58 had more than one ingredient. The most frequently covered category was "Disease and Health Promotion" followed by "Commercial Ads", "Korean style medicinal tea Culture", and others. From 355 articles, 188 provided the information on the efficacy of Korean style medicinal tea, 88 presented the pharmacological activity, 84 addressed the recipe, 80 explained the taste, and 31 included ancient literature. The most frequently covered tea were ginger tea, omija tea, gugija tea, jujube tea, mogwa tea. Autumn and winter had 109 articles, spring had 89, and summer had 86. Conclusions : This study showed the potential of Korean style medicinal tea as a successful future content. Most of the articles about Korean style medicinal tea contained information about the efficacy but practical information such as the recipe and drinking method were not addressed much. Therefore, future study is needed to investigate additional information about Korean style medicinal tea.

• Preventive Nutrition and Food Science
• /
• v.8 no.3
• /
• pp.284-288
• /
• 2003

In this study, we investigated the effects of green tea and Pueraria radix tea on the production of Apo B$_{100}$ in Hep G$_2$ liver cells and on the expression of the low density lipoprotein (LDL) receptor. Treatment with green tea resulted in a 60.7% decrease on the Apo B$_{100}$ concentration in Hep G$_2$ cells. Pueraria radix tea decreased Apo B$_{100}$ concentration by 63.5% in Hep G$_2$ cells. Green tea and Pueraria radix tea significantly decreased Apo B$_{100}$ concentration by 64.8% and 61.8%, respectively, in the media. Treatment of the cells with green tea and Pueraria radix tea also significantly decreased the intracellular total cholesterol, but total cholesterol concentrations in the media increased by 26.4% (green tea) and 23.6% (Pueraria radix tea) above that measured in the media of control cells. The addition of green tea and Pueraria radix to the media of the Hep Gz cells increased the LDL receptor binding activities by 84.1% and 79.4%, respectively.

• Journal of the East Asian Society of Dietary Life
• /
• v.16 no.1
• /
• pp.107-112
• /
• 2006

This study analyzed the changes of chlorophyll and ascorbic acid contents according to the extraction temperatures and the number of soakings using five kinds of Korean and Japanese green tea(3 kinds of green tea and 2 kinds of tea bag) which were obtained from local markets in Korea and Japan. The findings are as follows: 1. The chlorophyll contents of Japanese green tea were $2\sim3$ times higher than those of Korean green tea. 2. The chlorophyll contents of Korean green tea in high and middle grades were increased with increasing temperature $(80>70>60^{\circ}C)$ but the contents in low grade were increased with decreasing temperature. The contents of chlorophyll in Japanese green tea were almost similar in low, middle and high grades. 3. Ascorbic acid content was higher in low grade Korean green tea but it was higher in high and middle grades of Japanese green tea. Chlorophyll contents of Japanese green tea were higher than those of Korean green tea but ascorbic acid contents of Korean green tea were higher than those of Japanese green tea.

• Journal of Nutrition and Health
• /
• v.34 no.3
• /
• pp.285-298
• /
• 2001

The effects of dried leaf powders and water and ethanol extracts of persimmon and green tea on lipid metabolism, lipid peroxidation and antioxidative enzyme activity were investigated in 12-month-old rats. Forty-nine male Sprague-Dawley rats weighing 520$\pm$19g were blocked into seven groups according to body weight. Rats were raised for four weeks with control(no tea leaf powder or extracts) and experimental diets containing either 5%(w/w) dried leaf powders of persimmon(Diospyros kaki Thunb) or green tea(Camellia sinensis O. Ktze), or water or ethanol extract from equal amounts of each dried tea powder. Food intakes of all tea diet groups were higher than that of control. Weight gains and food efficiency ratios of all tea diet groups were not significantly different from those of control. All tea diets decreased plasma triglyceride level, especially, green tea powder and persimmon ethanol diets were more effective than other diet. All the tea diet groups showed decrease in liver triglyceride level, and persimmon powder and ethanol extract increased fecal triglyceride excretion. Plasma cholesterol levels of all the tea diet groups were not significantly different from the control, but control. Fecal cholesterliver cholesterol concegroups were significantlntrations of all tea y lower than that of ol excretions of persimmon powder, green tea ethanol extract, persommon ethanol extract and green tea ethanol extract groups were significantly higher than that of control. Plasma and liver thiobarbituric acid reactive substance(TBARS) concentrations of all the tea diet groups were lower than that of control. Especially, plasma TBARS concentrations of green tea powder and persimmon ethanol extract groups were sinificantly low. Red blood cell(RBC) superoxide dismutase(SOD) activities of persimmon ethanol extract and green tea water extract groups were increased, and RBC catalase activities of all experimental groups were not significantly different. RBC glutathione peroxidase(GSH-px) activities of persimmon ethanol extract, persimmon water extract and green tea powder groups were increased. Liver SOD activities of all the tea diet groups except green tea ethanol extract group were higher than that of control. Liver catalase activities of all experimental groups were not significantly different, and liver GSH-px activity of green tea powder group was significantly higher than that of control. In conclusion, dried leaf powders, and water and ethanol extracts of persimmon and green tea were effective in lowering lipid level, inhibiting lipid peroxidation and increasing antioxdative enzyme activities in 12-month-old rat. Green tea leaf powder with high contents of flavonoids and water soluble dietar fiber was most effective in lowering plasma triglyceride, cholesterol and TBARS level. (Korean J Nutrition 34(3) : 285~298, 2001)

• Preventive Nutrition and Food Science
• /
• v.7 no.3
• /
• pp.327-331
• /
• 2002

Tea is a pleasant, popular and safe beverage in the world. During the past decade, epidemiological studies have shown that tea catechins intake is associated with lower risk of cardiovascular disease. Tea provides a dietary source of health-promoting components to help humans reduce a wide variety of cancer risks and chronic diseases. The antioxidative activity of tea-derived catchins has been extensively studied. The antioxidant effect is a synergistic action between catechins e.g. EGCG, EGC, ECG, EC, pheophytins a and b, and other components in tea leaves, which aye more bioavailable for human body. Green tea has a Higher content of catechins than other kinds of tea. Green tea extract with hot water has high potential and more efficiency to reduce cancer risk than any other tea products or pure EGCG. Protein, iyon, and other food components may interfere with the bioavailability of ten catechins. Interaction of catechins with drug affects the cancer-preventive activity of some cancer-fighting medication. Further studies are required to determine the bioavailability of tea catechins and cancer-preventive functionality.

• The Korean Journal of Food And Nutrition
• /
• v.14 no.4
• /
• pp.311-316
• /
• 2001

This study was designed to investigate the effective ratio of healthy bread wish green tea powder. The weight. volume, and colon difference of bread with various contents of green tea powder were measured. And the picture of bread and the panel test were taken. To avoid the decrease of volume, the experiment was taken with active gluten. The weight to bread was increased and the volume was decreased significantly according to increase of green tea powder ratio. But, the volume of the group with active gluten(3%+ and 4%+) was higher than that of the group with green tea powder 2%. That is which the correction of the volute was taken by active gluten in green tea powder bread. In the result of panel test and volume measurement. addition of 3% green tea powder was appropriate, and the addition of active gluten corrected the decrease of volume. Therefore. using the green tea powder, the diversity of bread by functionality, nutritional composition. taste, color. flavor of green tea powder can be developed. This result will support the background the development of green tea bread of good quality.