• Journal of Nutrition and Health
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• v.34 no.5
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• pp.525-531
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• 2001

The present study investigated the protective effects of green tea against acute ethanol-induced lipid peroxidation and the change of antioxidative enzyme activities in various regions of rat brain : cortex, cerebellum, striatum and hippocampus. The following parameters were examined : malondialdehyde(MDA) levels and activities of superoxide dismutase(SOD), catalase and glutathione peroxidase(GSH-Px). Male Sprague-Dawley rats were given the experimental containing 1% green tea powder or control diet for 4 weeks, and at the end of feeding diet group received acute ethanol(5g/kg body weight) or equicaloric sucrose solution intragastrically. Green tea powder significantly decreased MDA levels in the striatum compared to control-non alcohol treated group to 1% green tea-non alcohol treated group without altering the antioxidative enzyme activities. Green tea resulted in a significant increase in GSH-Px activities in the hippocampus compared to either control-non alcohol treated group(0.043units/mg protein) or 1% green tea-non alcohol treated group(0.071units/mg protein). In conclusion, these results suggest that moderate consumption of green tea leaves can exert protective effects against ethanol-induced oxidative stress in brain regions, by reducing MDA concentrations in the striatum and enhancing GSH-Px activities in the hippocampus. (Korean J Nutrition 34(5) : 525∼531, 2001)

• The Korean Journal of Food And Nutrition
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• v.28 no.5
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• pp.766-773
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• 2015

This study analyzes the chemical composition of green tea, white tea, yellow tea, oolong tea and black tea with respect to extraction temperature and time. The optimum extraction conditions for these teas were determined by assessing the chemical composition of tea brewed at different temperature (50, 60, 70, $80^{\circ}C$) and extraction times (1, 3, 5, 10 minute). Catechins contents were the largest at 5 minutes and generally declined by 10 minutes. Green tea catechins contents were highest when brewed at $70^{\circ}C$ and besides other teas a change of the trend variation at 70 and $80^{\circ}C$. These temperatures did not extract theaflavins in green tea. Extract temperature and time did not significantly affect theaflavins content of white tea, yellow tea, and oolong tea. Black tea, however, was noticeably dependent on extract conditions, which were most effective at $70^{\circ}C$, brewed for 5 minutes. Caffeine content of green tea, yellow tea, and oolong tea was highest at 5 minutes, but temperature did not appear to affect the content. White tea and black tea caffeine content was highest when brewed at $70^{\circ}C$ for 5 minutes. Theobromine content of green tea, yellow tea, oolong tea, and black tea did not show major differences between the study times or temperature, though the content in white tea increased with higher temperatures when brewed for 5 minutes. The extraction of phenolic compounds increased until 5 minutes, and showed not further increase at 10 minutes. Antioxidant capacity of green tea, white tea, and yellow tea were maximized at $70^{\circ}C$ for 5 minutes or $80^{\circ}C$ for 3 minutes, while oolong and black tea were reached maximum antioxidants at $70^{\circ}C$ for 5 minutes. In general, to optimize the beneficial chemical content of brewed tea, a water temperature of $70^{\circ}C$ for 5 minutes is recommended.

• Journal of the Korean Society of Food Culture
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• v.18 no.3
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• pp.226-234
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• 2003

The effects of dried green tea leaf powders on serum lipid concentrations were evaluated in rats. Sixty male Sprague-Dawley rats weighing $100{\pm}10g$ were divided into six groups and fed high fat diets for six weeks. Experimental groups were administered with following diets; Normal fat diet and normal and high fat diets with 1% dried green tealeaf powders. Tissue weights of liver, lung, stomach, heart, kidney and spleen of high fat diet exposed rats were reduced by dried green tea leaf powders groups. The concentrations of serum triglyceride in rats fed the dried green tea leaf powders were lower than those in other groups. The concentrations of total cholesterol in green tea leaf powders the were lower than those in high fat diet groups. The concentrations of HDL-cholesterol in serum of the dried leaf powders green tea were significantly higher than those of other groups. The levels of LDL-cholesterol in serum of the dried green tea leaf powders groups were tended to be lower than those of other groups. GPT and GOT were decreased in dried green tea leaf powders groups and than in the high fat group. LDHase was lower in the dried green tea leaf powders groups than in the high fat group. These results suggest that dried leaf powders green tea groups may reduce elevated levels of serum lipid concentrations in rats fed high fat diets.

• The Korean Journal of Community Living Science
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• v.18 no.1
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• pp.107-129
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• 2007

The purpose of this research is to understand features of the present condition of green tea food by analyzing the data on tea foods presented in Korean literature after the 1990's (two articles from professional journals related to tea culture, and three books related to tea food). The main conclusions are as follows: 1. It is found from separating 354 different kinds of green tea foods into three categories - main dishes, side dishes and desserts - that there are 137 kinds of side dishes, 123 kinds of desserts, and 94 kinds of main dishes from green tea foods. Upon dividing these into smaller categories, there are 40 rice dishes, 27 noodle dishes, 18 gruel dishes and 9 dumpling dishes found among the main dishes; 26 pan fried dishes, 24 potherb/cooked potherbs dishes, 17 deep-fried dishes, 15 soup/broth dishes, 14 grilled dishes, 11 smothered dishes, 10 hard -boiled/fried dishes, 6 kimchi dishes, 4 dried food dishes, 4 jelly dishes, 4 stew dishes, and 2 raw fish dishes among the side dishes; and 37 snack dishes, 36 punch/drink dishes, 26 rice cake dishes, and 24 bread dishes are found among the desserts. 2. There are 201 kinds of green tea foods using powders, 107 kinds using wet tea leaves, 61 kinds using dry tea leaves, 57 kinds using water of drawn tea, and 17 kinds using wild tea leaves, according to analysis of teas used for green tea foods. There is more use of powder for snacks, punch and drinks, rice cakes, noodles, and breads, and more use of wet tea leaves for rice, pan fried food, and potherb/cooked potherb dishes. It is also shown that there is more use of water from drawn tea for rice, punch and drinks, noodles, and gruels, more use of dry tea leaves for snack, rice, breads, and more use of wild tea leaves for deep-fried and pan fried kinds of tea foods.

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

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.107-113
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• 2006

These studies were carried out to investigate the quality of green tea processed by different pan-firing hand rolling and to select the best conditions during the procedure of green tea processing the results were as follows. At harvestion tea plant leaf, tea plants had 4 leaves. each leaf size was 7.5 cm'$\square$2.6 cm, and weight of 100 buds 46.6 g. The increase of pan-fired time decreased in the moisture content and yield of green tea. After processing green tea, 5 times pan-fired one had much more contents of total nitrogen (T-N:5.31%), caffeine (2.00%) and total amino acid (T.A.A. : 3,046 mg%) and less content of tannin (13.41%) than the other treatments. but 3 times pan-fired one had the highest contents of vitamin C (204.3 mg%) and chlorophyll (365.0 mg%) among three kinds pan-firing method. Sixteen kinds of free amino acid including theanine as a good taste component of pan-fired green tea were isolated and measured by HPLC. Free amino acid (FAA) contents were in the range of $2,683{\sim}2,925$ mg% and among various pan-firing methods, 5 tims pan-fired one had the highest content of F.A.A. Among these free amino acids, theanine occupied as much as $56.4{\sim}61.3%$ of F.A.A. Lightness, yellowness and redness of 5 times pan-fired green tea were middle value among three different treatments. Besides, it gained the highest score of sensory evaluation among them. These above results suggested that 5 times pan-fired green tea was considered to be the best level as pan-firing times of green tea processing.

• Preventive Nutrition and Food Science
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• v.5 no.3
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• pp.165-169
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• 2000

Kombucha beverages were made from sweetened tea by Oriental, European and Tibetan tea fungus starters. The hot water extracts o green tea, black tea, Gugija and Omija were mixed with white and/or brown sugar, and were fermented under a static culture at 3$0^{\circ}C$. Titrable acidity, pH, color and cellulose production in kombucha beverages were evaluated. All tea fungus starters showed a higher acid production in green/black tea extracts rather than Gugija and Omija extracts. In green/black tea extracts Oriental tea fungus produced a kombucha beverage with a higher titrable acidity and lower pH than those of European and Tibetan tea fungus starters. By the static fermentation of green/black tea extract for 18 days, Oriental, Tibetan and European tea fungus starters produced cellulose pellicles of 0.43g, 0.16g, and 0.19 g (dry weight) on the top in the culture, respectively. As a mother starter, the cellulose pellicle was more efficient in acid production compared with tea fungus broth. Oriental/Tibetan mixed tea fungus showed the best acid production in the green/black tea extract supplemented with brown sugar.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.932-938
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• 2009

Browning of tea infusion is an obstructive factor influencing shelf life of ready-to-drink green tea. Effects of temperature and illumination on the browning of green tea infusion were investigated. It was shown that both elevated temperature and illumination led to the browning of green tea infusion, but temperature had greater effect on infusion color and level of catechins than illumination. The levels of unoxidized catechins such as (-)-epigallocatechin gallate (EGCg), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), (-)-epicatechin (EC), and total catechins remaining in the tea infusion were significantly correlated to color parameters of the tea infusion. Sodium ascorbate inhibited the infusion browning by suppressing the oxidation of tea catechins and it is considered to be a more suitable preservative for prolonging shelf life of ready-to-drink green tea than ascorbic acid because it has less effect on tea taste. The effects of temperature and illumination on the epimerization of catechins were also discussed.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1769-1774
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• 2005

This experiment was carried out to evaluate the effects of feeding green tea powder on laying performance and egg quality in hens. A total 180 'Tetran Brown' laying hens aged 40 weeks were assigned to 6 treatments in a completely randomized design. Each treatment consisted of five replicates accommodating six layers per replication. The experimental diets were a negative control containing no green tea, a positive control diet containing antibiotics (0.05% chlortetracycline) and diets containing 0.5%, 1.0%, 1.5% and 2.0% green tea powder. Egg production rate of layers fed the diets containing green tea powder did not differ significantly from that of the negative and positive controls (p>0.05). Egg weight was decreased significantly in the group fed the diet containing 0.5% green tea powder (p<0.05). Feed intake of layers was significantly higher for the diet containing 1.5% green tea powder compared to that of negative and positive control diets (p<0.05). The eggshell thickness reduced significantly in the layer group fed the diets containing green tea powder regardless of dietary levels (p<0.05). Green tea powder tended to reduce egg yolk cholesterol in this experiment. Particularly, dietary 2% level of green tea powder significantly suppressed the cholesterol contents of the egg yolk (p<0.05). Thiobarbituric acid value (TBA) of egg yolk was significantly reduced by green tea diets (p<0.05). The yellowness of egg yolk was increased in the layers fed the 2.0% green tea diet compared with that of control diet (p<0.005). The Linoleic and $\alpha$-linolenic acids tended to increase in the group fed diets containing 1.5% green tea powder even though there were no significant differences among treatments (p>0.05). The oleic and docosahexaenoic acid contents of the egg yolk were similar among treatments (p>0.05). Based on the results of the experiment, it is concluded that green tea powder inclusion in the diet for layers at 2.0% level can reduce the cholesterol content and TBA value of the egg yolk, implying its potential effect on egg quality parameters.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1339-1347
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• 2008

The objective of this study was to determine the effects of green tea probiotics on growth performance, meat quality and immune response in finishing pigs, and to assess the possibility of substituting green tea probiotics for antibiotics in diets of finishing pigs. This green tea probiotics is made by mixing green tea powder and excipients (defatted rice bran and wheat bran) and fermenting the mixture with beneficial bacteria. A total of 90 crossbreed "Landrace$\times$Yorkshire" finishing pigs with an average body weight of $72.5{\pm}2.5kg$ were assigned to 5 dietary treatments in a completely randomized design. Each treatment had 3 replications with 6 pigs per replication. The five dietary treatments were control, antibiotic (0.003% chlortetracycline added) and 0.1, 0.5 and 1.0% of green tea probiotics. There were no significant differences in final body weight, daily weight gain, daily feed intake and feed conversion ratio in the green tea probiotics and antibiotic treatments (p>0.05). Crude protein content was significantly increased in the 0.1 and 1.0% green tea probiotics treatment groups (p<0.05) and there was no significant difference in crude fat content of the meat among the treatments. The TBA value of meat was significantly lowered with 0.5 and 1.0% green tea probiotics treatments compared to that of controls and statistically similar to the antibiotic treatment after 3 weeks of storage (p<0.05). The growth of spleen cells stimulated with Con A (0.1 and $1.0{\mu}g/ml$) was significantly increased with 1.0% green tea probiotics treatment compared to that of the control treatment (p<0.05). The growth of spleen cells stimulated with LPS (1.0, 3.0 and $10{\mu}g/ml$) was significantly increased in the 0.5% green tea probiotics group compared to the antibiotic group (p<0.05). In Con A ($1.0{\mu}g/ml$) medium, IL-6 production of spleen cells was significantly increased with 1.0% green tea probiotics treatment compared to that of the control (p<0.05). In LPS ($10.0{\mu}g/ml$) medium, TNF-${\alpha}$ production of spleen cells increased significantly in all green tea probiotics treatment groups compared to that of the control (p<0.05). Finally it can be summarized that addition of green tea probiotic has a positive effect similar to antibiotic and 0.5% is the suitable dietary supplementation dose for finishing pig production.