• Nutritional Sciences
• /
• v.9 no.2
• /
• pp.61-67
• /
• 2006

Green tea has attracted attention with respect to its potential for preventing and treating neurodegenerative disease. The neurotoxin, 6-hydroxydopamine (6-OHDA), was used to produce experimental Parkinson's disease (PD) model. The purpose of this study was to investigate the effects of green tea diet on behavioral changes, striatal dopamine content, and hepatic antioxidant parameters of PD model rats. In this study, we used male Sprague-Dawley rats weighing $200\sim220g$ and injected 6-OHDA into the right substantia nigra and medial forebrain bundle of the brain. The supply of green tea diet was started at 2 weeks before 6-OHDA lesion and continually supplied during 0, 2, and 4 weeks after 6-OHDA lesion (GT-0, GT-2, GT-4). Behavioral disturbance was measured by the stepping and d-amphetamine drug-induced rotation tests. Then, we assayed the striatal dopamine content and the hepatic malondialdehyde (MDA), hydrogen peroxide $(H_2O_2)$, and superoxide dismutase (SOD) activity. The percentage of lesioned forepaw to non-lesioned forepaw step scores was the highest in GT-4 group among all groups at both 3 and 4 weeks after 6-OHDA lesion. At 4 weeks after 6-OHDA lesion, the rotation score was the lowest in GT-2 group (p<0.05). However, increasing rate of the rotation score from 2 to 4 weeks after 6-OHDA lesion was the lowest in GT-4 group. The striatal dopamine content was not significantly different among four groups by green tea diet. The hepatic MDA level was the lowest in GT-4 group among four groups. The hepatic SOD activity was increased with the prolongation of green tea diet period These results suggest that green tea diet affects behavioral changes in rats of PD model. It seems that continuous green tea supplementation has an influence on the reduction of behavioral disturbance and the hepatic MDA level. Accordingly, continuous green tea supplementation was recommended for the prevention and treatment of PD. However, further studies are needed to investigate the mechanisms and efficacy of green tea in PD.

• Journal of Nutrition and Health
• /
• v.31 no.6
• /
• pp.999-1005
• /
• 1998

This study was conducted to investigate the effect of late-harvested green tea extract on serum and tissue lipid contents and Ca absorption. Sprague-Dawley male rats weighing 200g were fed high fit diets containing no tea(control), 0.5%(0.5LG), 1.0% late-harvested green tea extract(1.0LG), and 1.0% early-harvested green tea extract(1.0EG) for 4 weeks. Though daily food intake of experimental groups showed no significant difference from that of control group, daily body weight gain and food efficiency ratio were lower in all groups fed green tea extract. The contents of serum triglyceride of 1.0LG and 1.0EG groups and the content of serum total cholesterol of 1.0LG group were significantly lower than those of control group. The values of serum HDL-cholesterol in groups fed green tea extract were higher than that in the control group. LDL-cholesterol and atherogenic indices of all groups fed green tea extract were significantly lower than those of the control group. The contents of total lipid and triglyceride in liver were significantly lower in only 1.0LG group. For epididymal fit pad, the contents of total lipid and triglyceride in 1.0LG and 1.0EG groups were lower than those in the control group. The contents of total lipid excreted in feces were higher in groups fed diets of 1.0% green tea extract. There was no significant difference among experimental groups in Ca absorption. These results suggest that the administration of late-harvested green tea extract decreases the contents of fat in the body without reducing Ca absorption. (Korean J Nutrition 31(6) : 999-1005, 1998)

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.7
• /
• pp.1021-1025
• /
• 2003

The study was to investigate the quality of wet noodle added with the powder green tea. The wet noodles were prepared to the ratio of 1, 2, 3, 5, 7.5 and 10% (w/w) of the powder green tea based on a flour weight. The initial pasting temperature in an amylograph was increased as the increase of the powder green tea, while peak and final viscosity as the increase decreased. The weight and volume of cooked noodles were decreased, and turbidity of soup was increased with the addition of the powder green tea. L and a values of wet noodles were decreased with the addition of the powder green tea, and b value was increased. Texture profile analysis of cooked noodle showed a increase of hardness, cohesiveness, springiness, chewiness up to 2% powder green tea, but decreased from 3% power green tea. However, adhesiveness decreased as the increase of the powder green tea. From the sensory evaluation, the wet noodles included 1% powder green tea were similarly evaluated as the noodle used whole wheat flour.

• Applied Biological Chemistry
• /
• v.31 no.3
• /
• pp.284-291
• /
• 1988

To establish the evaluation method of Korean green tea, the correlation between physicochemical characteristics and sensory scores by the expert panels were investigated using 15 kinds of green tea manufactured in 1985 from Korea, Taiwan and Japan. Tannin, caffeine and total free amino acid contents of Korean green tea are higher than foreign ones, but the chlorophyll content is the highest in Japanese high grade green tea. Sixteen free amino acids including theanine were identified, and theanine, glutamic acid, aspartic acid and arginine contents which affect the brothy taste of green tea infusion were highest in Korean green tea. Sensory score for the color of Korean green tea infusion were lower than Japanese tea, but the flavor and taste were the best. In multiple regression analysis, the quality affecting factors of the green tea were elucidated as the caffeine$(X_1)$, chlorophyll b$(X_2)$, total free amino acid contents$(X_3)$, and L value$(X_4)$ of green tea infusion. The regression equation was expressed as $Y=-21.5820+2.1691X_1+0.0130X_2+0.2314X_3-0.0001X_4$ and then $R^2$ was 0.8919.

• The Korean Journal of Food And Nutrition
• /
• v.31 no.3
• /
• pp.416-424
• /
• 2018

The physiologically advantageous aspects of green tea have been identified recently and green tea has been a favorite drink of many people. Due to the increased awareness of green tea's positive effects on human health, the demand for foods containing green tea has increased. This has led to the development of diverse green tea-related beverages; thereby many companies in Korea have put a wide variety of manufactured green tea beverages on the market. However, the components within green tea beverages have not been examined in Korea yet. In this study, we investigated the contents of the physiologically functional materials found in green tea, such as catechin, catechin gallate, epicatechin, epicatechin gallate, epigallocatecin gallate, gallocatechin gallate and caffeine. Fifty-six green tea products purchased from the local grocery stores and cafes were analyzed using high performance liquid chromatography (HPLC) analysis. As a result, all tested products contained catechin and caffeine, although the amount of each component was largely different. The total amount of catechin derivatives in the manufactured green tea beverages purchased from cafes was 263.17 mg/L, while they were 61.99 mg/L in the beverages purchased from the local grocery stores. And, to the almost samples the amount of caffeine was proportional to the amount of catechin.

• The Korean Journal of Community Living Science
• /
• v.16 no.1
• /
• pp.59-64
• /
• 2005

This study is to find out effects of hot water soluble extract from green tea, one of the Korean favorites, on the calcium metabolism and bone strength in body. To do so, calcium, phosphate, creatinine concentration and ALP activity in blood and the content of calcium and ash in the organ, the length, weight, strength in bone were measured. In addition, to find the calcium metabolism, the level of calcium intake, excretion, retention were measured. Twenty male Sprague-Dawley rats were divided into two groups and isoloated soy protein was provided as the source of protein and CaCO₃ was provided as the source of calcium. 0.5% hot water soluble extract from green tea was provided to the green tea groups and for the control group deionized water was provided. The results are as follows ; 1. There is no difference between the experimental groups in diet intake, weight gain, and the feed intake. 2. Feed efficiency ratio was low in the group which hot water soluble extract from green tea was provided. 3. There is no difference between groups the level of calcium, phosphorus, creatinine and ALP activity in serum. 4. There is no difference between groups weight, contents of ash and calcium in kidney and liver. 5. There is no difference between groups in calcium intake, absorption, excretion, and retention. 6. There is no difference between groups weight, length and strength in bone. In summary, when hot water soluble extract from green tea was provided with the amount of 150-200mg, which is taken when people generally drink as favorite tea, weight gain was reduced due to the decrease of feed efficiency ratio. However, it did not affect the availability of calcium in body at all. Thus, even if a big quantity of green tea powder or solid of hot green tea extract is not provided, the quantity obtained when people drink green tea lowers the feed efficiency ratio without reducing availability of calcium in body.

• Culinary science and hospitality research
• /
• v.16 no.4
• /
• pp.220-229
• /
• 2010

Brewing tea with regular teapots can cause a problem in keeping the temperature of the tea. Cold weather, a cold teapot, and/or the temperature of tea leaves make tea cold, lowering the temperature of the tea leaves that can also make the flavor of the tea leaves worse. This experiment shows both the problem and the solution to the temperature problem of tea leaves. To maintain the appropriate temperature and reduce the problem, we researched and developed a special straw for tea leaves as a result of this experiment The straw consists of various filtering holes(diameter 1~2 mm) with the height of 5 mm from the very bottom of the straw. Using the straw is better to keep higher temperature, better flavor, and the smell of tea. Also, the sensory evaluation shows that the overall taste of tea is improved(p<0.05).

• Journal of Applied Biological Chemistry
• /
• v.55 no.2
• /
• pp.95-101
• /
• 2012

Nutritional components of Ojuk leaf tea and Ojuk shoot tea prepared from the leaves and shoots of black bamboo (Phyllostachys nigra Munro) by tea manufacturing process were evaluated. In addition, the extraction yield of water soluble components from these teas in the general tea brewing condition (water extraction in $80^{\circ}C$ for 10 min.) and the contents of polyphenol and flavonoid were compared with not only the dried raw materials, but also green tea and mate tea. Finally, offline and online scavenging activities against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and di(phenyl)-(2,4,6 trinitrophenyl)iminoazanium free radicals were investigated to evaluate the antioxidant activity and explore the components showing ABTS free radical scavenging activity from tea infusion. These results demonstrated that these teas from black bamboo contain various nutritional components and can be used as traditional tea beneficial to human health.

• The Korean Journal of Food And Nutrition
• /
• v.30 no.5
• /
• pp.908-915
• /
• 2017

This study was performed to determine the effects of different processing methods (AD: drying at $50^{\circ}C$ for 15 h; ADR: roasting after drying; SAD: drying after steaming; SADR: roasting after steaming and drying) on the quality characteristics, total phenolic content, anthocyanin content, DPPH radical scavenging activity, and reducing powder of red radish (Bordeaux and watermelon radish) tea. The pH of red radish tea was the highest with SAD. In terms of the total sugar content, Bordeaux radish tea showed the highest level with AD, ADR, and SAD, and watermelon radish tea showed the highest level with SADR. The a value of Bordeaux radish tea was higher with AD and ADR. The b value of Bordeaux radish tea was increased with steaming and roasting treatment. In terms of measuring the colors of watermelon radish tea, the L value was decreased while the b value was increased with roasting treatment. The total phenolic content, DPPH radical scavenging activity, and reducing powder with ADR and SADR were higher than those in samples prepared by different processing methods. AD and SAD resulted in higher anthocyanin contents than ADR and SADR. In terms of sensory evaluation, the appearance and color were rated higher with AD and SAD, whereas the flavor and taste were ranked higher with ADR and SADR than in the other samples. The results suggest that red radish (Bordeaux and watermelon radish) tea prepared by ADR and SADR processing methods can be utilized as health functional tea material with antioxidant activity.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.12 no.4
• /
• pp.77-85
• /
• 2002

We present the impossible differential cryptanalysis of the block cipher XTEA[7] and TEA[6]. The core of the design principle of these block ciphers is an easy implementation and a simplicity. But this simplicity dose not offer a large diffusion property. Our impossible differential cryptanalysis of reduced-round versions of XTEA and TEA is based on this fact. We will show how to construct a 12-round impossible characteristic of XTEA. We can then derive 128-bit user key of the 14-round XTEA with $2^{62.5}$ chosen plaintexts and $2^{85}$ encryption times using the 12-round impossible characteristic. In addition, we will show how to construct a 10-round impossible characteristic or TEA. Then we can derive 128-bit user key or the 11-round TEA with $2^{52.5}$ chosen plaintexts and $2^{84}$ encryption times using the 10-round impossible characteristic.