• 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.

• Food Science and Preservation
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• v.11 no.2
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• pp.175-181
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• 2004

As a foundational study for notifing excellence of persimmon leaves tea, the chemical component and antioxidant activity were investigated in persimmon leaves from Dungsi, Gabjubaekmok, Weulhasi and Cheongdobansi and green tea leaves. Total sugar contents in all persimmon leaves more higher than that of green tea leaves, and the highest free sugar contained in persimmon and green tea leaves was sucrose. Free sugars present in persimmon and green tea leaves were composed of sucrose, glucose, fructose, maltose and xylose. Sucrose and fructose took more than 70% of total sugar contents. 31∼32 kinds of amino acid were detected in persimmon leaves and 35 kinds in green tea leaves. And total amino acids contained in persimmon leaves were Dungsi, Gabjubaekmok, Weulhasi and Cheongdobansi, respectively 60.40 nmol/${\mu}$L, 53.21 nmol/${\mu}$L, 52.29 nmol/${\mu}$L and 47.58 nmol/${\mu}$L. Total amino acid contents in green tea leaves was the most abundant of all as 114.72 nmol/${\mu}$L. The contents of vitamin C in persimmon and green tea leaves were in the range of 0.015∼0.089% and 0.01%, respectively. Vitamin C was significant higher content in the persimmon leaves than in green tea leaves. Caffeine was not detected in all persimmon leaves, but the caffeine content of green tea leaves was 6.63 mg/l00 g. The content of catechin was showed in the orders of Cheongdobansi, Gabjubaekmok, Weulhasi, Dungsi and green tea leaves; 0.35%, 0.34%, 0.24%, 0.18% and 0.07%, respectively. The contents of gallic acid in Dungsi and Gabjubaekmok were 0.32% and 0.20%. That of green tea was 1.41%, it was the highest content in all samples. The content of calcium in Chengdobansi was most abundant in all samples as 3516.14 ppm, it was 4∼5 times as that of green tea leaves. Flavor component pattern among persimmon leaves was similar, but that of green tea leaves was different. The IC50(${\mu}$g) value of Dungsi, Weulhasi, Gabjubaekmok, Cheongdobansi and green tea were 64.5, 42.0, 47.0, 64.0 and 19.0 respectively.

• Korean Journal of Food Science and Technology
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• v.39 no.3
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• pp.246-254
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• 2007

Fresh tea leaves grown in Jeju Island and Jeonnam Province of South Korea were plucked and processed. Volatile compounds (VCs) were analyzed and identified with SPME-GC/GC-MS/GC-O. The VCs of green teas were classified into two major categories based on their aroma characteristics: the Greenish (Group I), and Floral (Group II) odorants. It was found that the VCs were decreased significantly in fresh tea leaves as they were plucked at the later stages of cultivation. The ratio of VCs responsible for Group I and Group II compounds was well-balanced in tea leaves plucked in May, but the balances were changed when the fresh leaves were processed. The major VCs of fresh tea leaves in Jeju and Jeonnam were n-hexanal, E-2-hexenal, Z-3-hexenal, myrcene, benzyl alcohol, linalool, and phenyl alcohol. Also, Jeju and Jeonnam tea leaves had different aroma composition. n-Heptanol, ${\beta}-pinene$, benzaldehyde, and ethyl salicylate were found in Jeju fresh tea leaves, and Z-3-hexenol, E-2-hexenol, and methyl n-heptanoate were detected in Jeju dry tea leaves. On the other hand, Z-linalool oxide and myrcene were found in Jeonnam dry tea leaves. The SPME-GC method showed high reproducibility (RSD, 7.4%) with no-artifact formation. In this study, optimum plucking period of tea leaves could be determined for production of high quality green tea with a well-balanced aroma and characteristic VCs in green tea according to growing areas.

• Preventive Nutrition and Food Science
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• v.12 no.1
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• pp.35-39
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• 2007

This study was conducted to investigate the effects of soil selenium (Se) supplementation level on Se contents of green tea and milk vetch. Four different concentrations of sodium selenite ($Na_2SeO_3$) solutions (0.0, 3.3, 33.0 and 165.0${\mu}g/mL$) were prepared and one liter of each solution was well mixed with 10 kg of compost (cowpea soil) to give four different levels of Se-containing soil: $T_1$, 0; $T_2$, 33; $T_3$, 330; $T_4$, and 1,650${\mu}g$/100 g soil. Green tea plants and milk vetch were individually cultivated in those soils for 60 days. Se contents of freeze-dried green tea leaves were 6.87, 10.40, 12.04, and 20.19 ${\mu}g/g$, respectively; all of which were significantly different (p<0.05) from the others except for $T_2$ and $T_3$. The results showed that Se-contents of green tea leaves were increased 1.5$\sim$2.9 times as the Se level in the soil increased. Regression equation between Se contents in green tea (Y) and soil Se supplementation level (X) was: Y=0.007X＋8.857. However, Se contents in the milk vetch were increased significantly (p<0.05) more with the same treatments $T_3$ (74 ${\mu}g/g$) and $T_4$ (187$\mu$g/g) in comparison to those at $T_1$ (5.0 ${\mu}g/g$) and $T_2$ (12.0$\mu$g/g). The increases ranged from approximately between 2.4 to 37.4 times that of the control group. Regression equation between Se contents in milk vetch (Y) and soil Se supplementation level (X) was: Y=0.1063X＋15.989. The large difference of Se contents between green tea leaves and milk vetch would be attributed by the difference of protein contents between the 30% or higher protein-content of legumes and 15$\sim$20% protein of shrubs. The present study clearly indicates that green tea leaves and milk vetch can be enriched in selenium by supplementing the soil with Se. Therefore, Se-enriched green tea or milk vetch powder could be utilized as functional foods in Se-fortified green tea drinks or salads, or as food additives to enhance the daily intake of Se.

• Bulletin of the Korean Chemical Society
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• v.26 no.5
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• pp.747-754
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• 2005

Liquid chromatographic methods with UV and fluorescence detection have been used to determine the levels of (+)-catechin, (-)-epicatechin, (-)-epicatechin gallate, and (-)-epigallocatechin gallate in Korean green tea infusions. The extracts of Korean green tea leaves or powders in water at various temperatures (100 ${^{\circ}C}$, 80 ${^{\circ}C}$, 60 ${^{\circ}C}$) and time, were washed with chloroform and re-extracted to ethyl acetate. The ethyl acetate phase was dried and re-dissolved in methanol and analyzed. Five catechin compounds were separated by gradient elution. The flavonoids were found decomposed on prolonged extraction, thus exhaustive extraction by a Soxhlet apparatus was found useless for green tea. Some unknown components were found in the extracts at 100 ${^{\circ}C}$. When the green tea was filtered and re-extracted with new fresh water, still some flavonoids were extracted. However, the contents of flavonoids in the third extract were found negligible. The flavonoid extraction rate of green tea powders was higher than that of green tea leaves, but flavonoid decomposition of green tea powders was also faster than that of green tea leaves. The traditional way of drinking green tea was found appropriate in view of flavonoids intake.

• Korean journal of food and cookery science
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• v.15 no.2
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• pp.95-101
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• 1999

This study was carried out to prepare green teas by traditional roasting manufacturing process, Ku Geung Ku Po and to determine the quality charateristics of the green teas by examining the change of their main components induced during this roasting process. The content of total sugars in unroasted tea leaves was 7.82%. Its content of roasted teas was decreased by increasing the number of roasting and there was significantly differences between samples. The content of total sugars in 9th roasted green tea was 3.98%. The total nitrogen contents of green teas produced by this process were 4.96∼6.38%. The more the number of roasting and the less content of tannin in green teas. And the ratio of total nitrogen and tannin in tea leaves 21.97 but its ratio in 9th roasted tea was increased to 45.54. The ascorbic acid in tea leaves consisted in 1,820.3 mg/100g but its content was decreased by increasing the number of roasting process. Whereas the content of caffeine in green teas was not reduced significantly by this traditional method. Of all amino acids, green tea produced by Ku Jeung Ku Po was rich glutamic acid, lysine and aspartic acid. And especially, phenylalanine, which was rarely found in other green teas, was abundant in these green teas. The compositions of glutamic acid and methionine were increased as increasing the number of roasting process but those of aspartic acid and arginine decreased by these processing. The main fatty acids of Ku Jeung Ku Po green tea were linolenic acid, linoleic acid and palmitic acid and the contents of unsaturated fatty acid in green teas were composed over 70% of total fatty acid. And the fatty acid contents in green teas were not affected during Ku Jeung Ku Po's process. The contents of minerals in these teas was rich in the oder of potassuim. magnessuim and calciumim, and these contents were not observed the prominant change during the process.

• Nutrition Research and Practice
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• v.6 no.2
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• pp.106-112
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• 2012

This study was conducted to investigate the effects of $Sasa$ $quelpaertensis$ bamboo and green tea on plasma and liver lipids, platelet aggregation, and erythrocyte membrane Na channels in ovariectomized (OVX) rats. Thirty female rats were OVX, and ten female rats were sham-operated at the age of 6 weeks. The rats were divided into four groups at the age of 10 weeks and fed the experiment diets: sham-control, OVX-control, OVX-bamboo leaves (10%), or OVX-green tea leaves (10%) for four weeks. Final body weight increased significantly in the OVX groups compared with that in the sham-control, whereas body weight in the OVX-green tea group decreased significantly compared with that in the OVX-control ($P$ < 0.01). High density lipoprotein (HDL)-cholesterol level decreased in all OVX groups compared with that in the sham-control rats ($P$ < 0.05) but without a difference in plasma total cholesterol. Plasma triglycerides in the OVX-green tea group were significantly lower than those in the sham-control or OVX-control group ($P$ < 0.05). Liver triglycerides increased significantly in the OVX-control compared with those in the sham-control ($P$ < 0.01) but decreased significantly in the OVX-green tea group compared with those in the OVX-control or OVX-bamboo group ($P$ < 0.01). Platelet aggregation in both maximum and initial slope tended to be lower in all OVX rats compared with that in the sham-control rats but was not significantly different. Na-K ATPase tended to increase and Na-K cotransport tended to decrease following ovariectomy. Na-K ATPase decreased significantly in the OVX-green tea group compared with that in the OVX-control group ($P$ < 0.01), and Na-K cotransport increased significantly in the OVX-bamboo and OVX-green tea groups compared with that in the OVX-control ($P$ < 0.05). Femoral bone mineral density tended to be lower in OVX rats than that in the sham-control, whereas the green tea and bamboo leaves groups recovered bone density to some extent. The results show that ovariectomy caused an increase in body weight and liver triglycerides, and that green tea was effective for lowering body weight and triglycerides in OVX rats. Ovariectomy induced an increase in Na efflux via Na-K ATPase and a decrease in Na efflux via Na-K cotransport. Furthermore, consumption of green tea and bamboo leaves affected Na efflux channels, controlling electrolyte and body water balance.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.49-58
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• 2008

This research was carried out to use green tea leaves powder for scavenging effects of volatile organic compounds on the UV varnishes and adhesives of fancy cherry veneer overlaid on the PF resin bonded Meranti plywood. The results are as follows: 1) Green tea leaves contained 9.85% of polyphenol compounds. 2) FT-IR results showed green tea leaves had effects to react with benzaldehyde and ethyl hexyl alcohol to form a chemical bond. 3) 2.5% of green tea leaves powder content was proper for scavenging effect on the UV varnishes and adhesives of fancy veneer overlaid on the PF resin bonded plywood 4) 20 liters small chamber test indicated excellent emission speed results such as $0.089mg/m^2hr$ of TVOC and $0.001mg/m^2hr$ of HCHO (on 7th day), as compared with standard (less than $0.1mg/m^2hr$ of TVOC and $0.015mg/m^2hr$ of HCHO emission are the excellent grade).

• Journal of the East Asian Society of Dietary Life
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• v.24 no.2
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• pp.183-189
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• 2014

We investigated noodles supplemented with functional ingredients for their antioxidant properties, including total phenol, flavonoid contents, electron donating, nitrite scavenging abilities and ferrous ion chelating effect. The total polyphenol contents of functional noodles arranged in order of decreasing concentration were kudzu (7.98%) > green tea (4.99%) > pumpkin (5.03%) > mulberry leaves (4.99%) > mugwort (4.23%) > cactus (3.57%) > kelp (3.33). The total flavonoid contents in green tea noodles were the highest as 4.35%. The electron donating ability in mugwort noodle was the highest as 12.27% at 1,000 ppm. This amount was 4.85 times than that of wheat flour noodle (2.53%). The nitrite scavenging ability of functional noodles at pH 1.2 arranged in order of decreasing concentration were green tea (66.52%) > cactus (55.12%) > kudzu (52.67%) > pumpkin (50.50%) > mulberry leaves (43.58%) > kelp (41.41%) > mugwort (37.66). The nitrite-scavenging ability of green tea noodle was lower than ascorbic acid (natural antioxidant) 77.83%, while that of green tea noodle was similar with BHT (artificial antioxidant) 69.45%. The ferrous ion chelating effect of noodles containing kelp were the highest as 27.02%. All of the experimental results showed good antioxidant property. Thus, noodles supplemented with mulberry leaves, cactus, mugwort, green tea, pumpkin, kelp or kudzu, demonstrated to have good functional effects for human health.

• Journal of Soil and Groundwater Environment
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• v.22 no.5
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• pp.128-134
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• 2017

This work presents the adsorption capability of green tea and ginseng leaves to adsorb heavy metals such as Cd(II), Cu(II), and Pb(II) in aqueous solution. FT-IR analysis indicates the presence of oxygen containing functional groups (carboxyl groups) in two kinds of leaves. High pH condition was favorable to the adsorption of heavy metal ions due to the enhanced electrostatic attraction and the precipitation reaction of metal ions. The adsorption of Cd(II), Cu(II), and Pb(II) reached equilibrium within 10 min, achieving high removal efficiencies of 80.3-97.5%. The adsorption kinetics data of heavy metal ions were fitted well with the pseudo-second-order kinetic model. The maximum adsorption amounts of Cd(II), Cu(II), and Pb(II) ions were 8, 3.5, and 15 mg/g, respectively, in the initial concentration range from 0.15 to 0.75 mM. Based on the fitting data obtained from isotherm models, heavy metal adsorption by green tea and ginseng leaves could occur via multi-layer sorption.