• Journal of the Korean Society of Food Culture
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• v.20 no.1
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• pp.103-112
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• 2005

The objective of this study was to clarify the effect of addition of green tea powder(0%, 2%, 4%, 6%, 8%) to Yackwa on quality and preservation. Addition of 4% green tea powder turned out to give positive effect on expansion. In test of physical characters, addition of green tea powder had a tendency to lower hardness, cohesiveness, springness and gumminess but to enhance brittleness. Considering the rancidity of oil within Yackwa, addition of green tea powder tended to show lower acid value and peroxide value than non-added treatment but its difference was slight. At the sensory test, surface color, bitterness and green tea flavor were strong but sweet and savory taste weak when green team powder was added(p<0.05). Overall quality appeared to have improved to 5.55 points which is compared to non-addition when the powder was added 4%(p<0.05). In conclusion, 4% addition of green tea powder would be the usefull method to enhance preference and quality of Yackwa.

• Journal of the Korean Home Economics Association
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• v.44 no.9
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• pp.21-29
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• 2006

The purpose of this study was to investigate the preferences and utilization of green tea and its products for adults living in Chonbuk area. Self-administered questionnaires were collected from 388 (117 male, 271 female) subjects. who were classified into 5 groups by age. Data were analysed by chi-square and ANOVA. The results can be summarized as follows. On the investigation of preferences, there was a significant difference between and among the age groups(p<.001). More than 20% of the subjects in the $20{\sim}29$ years group preferred coffee and juice. A half of the elderly over 60 years preferred a kind of green tea. The frequency of green tea drinking was not significantly influenced by age. Drinking green tea less than once a day was replied by 59.0% of the subject of whom 44.3% drank the green tea at home. and 42.0% got information about green tea from TV or radio. Regarding the satisfaction with products using green tea, 62.6% of the subjects responded only 'mediocre.' The brown rice-green tea was marked to be the highest in terms of recognition among all kinds of products. The green tea-related products were rated higher by the elder group. In conclusion, future research should focus on the development of green tea and its products in accordance with the consumption pattern in each age group.

• Journal of the East Asian Society of Dietary Life
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• v.15 no.1
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• pp.57-64
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• 2005

The effects of water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower on serum lipid concentrations were evaluated in rats. Forty-eight male Sprague-Dawley rats weighing l00±l0 g were divided into six groups and fed high fat diets for six weeks. Experimental groups were administered with following diets; Control diet, animal, plant high fat diet and control and high fat diets with 2% water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower. Tissue weights of liver, lung, stomach, heart, kidney and spleen of high fat diet exposed rats were reduced by water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups. The concentrations of serum triglyceride in rats fed the water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower were lower than those in other groups. The concentrations of total cholesterol in water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower group were lower than those in high fat diet groups. The concentrations of HDL-cholesterol in serum of the water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups were significantly higher than those of other groups. The levels of LDL-cholesterol in serum of the water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups were tended to be lower than those of other groups. GPT and GOT activities were decreased in water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups and than in the high fat group. LDH activity was lower in the water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups than in the high fat group. These results suggest that water extracts of green tea scented with lotus Nelumbo nucifera Gaertner flower groups may reduce elevated levels of serum lipid concentrations in rats fed high fat diets.

• Journal of Forest and Environmental Science
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• v.36 no.2
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• pp.156-162
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• 2020

This study was conducted to analyze the current management status of green tea processors in two regions (Hadong-gun and Boseong-gun) in Korea and to suggest directions for the development of the green tea industry based on an understanding their difficulties in management. This study showed that the number of green tea farms and the cultivation area had decreased, while the average unit sales price of green tea in Boseong-gun was approximately three times higher than that in Hadong-gun. Also, this study found that Hadong-gun mainly provided green tea products to wholesalers, whereas Boseong-gun sold it directly to the local retail stores targeting tourists, and this results in generating relatively higher unit prices. Meanwhile, we discovered that both regions had difficulties in management which were caused by the demand for low delivery unit costs from large corporations and small food companies. Therefore, in order to develop the green tea industry in both regions, the size of green tea fields and the scenery satisfaction should be improved to draw more tourists and boost tourists' intention to revisit. In addition, it is necessary to enhance guidance and accessibility of related tourist sites, to expand green tea experience activities, and to improve product satisfaction by developing various goods. By inducing more tourists in these ways, it could change the sales type of green tea from wholesale to retail and help activate the management of green tea processors.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.4
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• pp.447-452
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• 2006

This study examined the growth and sensory characteristics of soybean sprout cultured at 25$\pm$1$^{\circ}C$ for 4 days with distilled water control and green tea extracted water (0.03% and 0.05%). The proximate composition of soybean sprout in the green-tea water was better than that of the control in ash, protein and fat, while the soybean sprout was especially higher in 0.05% green-tea water. The contents of vitamin C and $\beta$-carotene were higher in soybean sprout in green-tea water than the control. The total free amino acids composition of soybean sprout in green-tea water was better than that of the control, with the highest being obtained in soybean sprout in 0.03% green-tea water. Antioxidative activity was assayed by DPPH radical scavenging ability with spectrophotometer at 514 nm. The soybean sprout in green-tea water was higher than control. The amylase activity of the soybean sprout increased steadily during the first 4 days and that of the control was higher than soybean sprout in green-tea water. The proteinase of soybean sprout steadily increased during 4 day culture. Furthermore, the proteinase activity of soybean sprout in green-tea water was higher than that of the control up to 2 days. Whereas after 3 days, it was the highest in 0.03% green-tea water and then decreased remarkably in 0.05% green-tea water.

• Journal of the Korean Society of Food Culture
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• v.20 no.5
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• pp.532-537
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• 2005

This study was carried out to clarify the effect of addition of green tea powder on Dasik quality. The green tea powder was added as the ratio of 0%, 2%, 4%, 6% and 8%, respectively. The physio-chemical analysis and sensory test on the Dasik were performed. The flour and starch Dasik added to green tea powder showed lower moisture content compared to the non-added treatment, but the ash content was higher in the added Dasik. At the color test, Dasik of green tea powder showed lower L, a, and b value than the non-added treatment, respectively. These values were greatly decreased as the amount of green tea powder was increased. Addition of green tea powder had a tendency to show high hardness, cohesiveness, springiness, and gumminess but brittleness was low in the non-added treatment. Therefore, addition of green tea powder made Dasik texture more dense, and this tendency of texture was distinct at the flour Dasik compared to the starch Dasik. At the sensory test, surface color and green tea flavor were strong as the adding amount of green tea was increased, but sweetness was weak. There were not significant differences in the overall preference among 0%, 2% and 4% treatments, but the preference was greatly decreased from the above 6%. In conclusion, 4% addition of green tea powder would be the useful method to enhance quality of Dasik, and the flour Dasik showed better result than the starch Dasik.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.299-304
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• 1995

Antioxidative effect of tea extracts from green tea(steamed, roasted), oolong tea and black tea was investigated. Antioxidative activities of the crude catechin fraction were the most effective in oolong tea which contained the highest level of (-)-epigallocatechin gallate(EGCg). The water-soluble fraction obtained from oolong tea exhibited binding with more ferrous than copper ions. It showed a synergistic effect when used with an antioxidant such as BHT(0.5mg) and $\alpha$-tocopherol(2mg). Especially, this synergistic effect was exhibited more with BHT than with $\alpha$-tocopherol. Also steamed green tea, roasted green tea and oolong tea showed remarkable free radical scavenging action. The SC50(the concentration of a water-soluble fraction which is required to scavenge 50% of 100$\mu$M 1, 1-diphenyl-2-picryl hydrazyl radicals) of steamed and roasted green tea, oolong tea and black tea extracts were 11.3$\mu\textrm{g}$/ml, 11.4$\mu\textrm{g}$/ml, 12.7 $\mu\textrm{g}$/ml and 14.9$\mu\textrm{g}$/ml, respectively. It is assumed that the antioxidative activity of tea extracts is due to inhibition of peroxidation free radical scavenging and binding action of ferrous ions by mainly tea polyphenol compounds.

• Korean Journal of Medicinal Crop Science
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• v.14 no.6
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• pp.322-328
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• 2006

Green tea is of particular source as it has been found to have strong antioxidant activities. The extracts of green tea during the commercial harvest seasons from April, 2003 to August, 2003 were compared. The purpose of this study was to determine the correlation between the polyphenol content of green teas and its antioxidant activities. The con-tent of total polyphenols was analyzed and several antioxidant testings were performed. The levels of total polyphenols were higher in the green teas (e.g. Woojeon, Sejak) harvested during very early spring and lower in the green teas harvested late(eg. Ipha, Yepcha). In particular, the free radical scavenging, the inhibition of LDL oxidation, the cytoprotective effect and the inhibition of DNA damage were correlated with the total polyphenol contents of green tea extracts harvested early spring such as Woojeon, Sejak and Jungjak. The results obtained here show that all extracts of green teas including purified green tea catechin, GTC, have strong antioxidant activities on oxidative stress in vifrθ. The variation in polyphenol content and antioxidant activities among various types of green tea by the harvesting time may provide critical information for investigators and consumers using tea in purposes of nutrition and chemoprevention.

• Nutritional Sciences
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• v.8 no.3
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• pp.175-180
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• 2005

Green tea, which has high polyphenols amount, is thought to have hypocholesterolemic effects. The present study was performed to further examine the hypocholesterolemic action of green tea, especially (-) epigallocatechin gallate (EGCG) for its effect on diet-induced hypercholesterolemia in rats. Male Sprague-Dawley rats (n=15) were fed a green tea-free diet (control), $1.0\%$ green tea catechin (catechin) or $0.5\%$ green tea catechin EGCG for seven weeks. Hypercholesterolemia was induced by adding $1\%$ cholesterol and $0.5\%$ cholic acid to all diets. There was no difference in food intake and body weight gain among the groups. The green tea EGCG treatment led to a significant improvement in plasma levels of total cholesterol, low density lipoprotein (LDL)-cholesterol and high density lipoprotein (HDL)/LDL ratio (p<0.05). There was no significant effect on the plasma HDL-cholesterol level. The catechin treatment led to a 4.19-fold increase in the LDL-receptor mRNA level compared to the control, but the EGCG treatment did not affect the hepatic LDL-receptor mRNA level. Our results suggest that when blood cholesterol level is down-regulated by green tea EGCG, the LDL receptor gene-independent pathway may dominate the hypocholesterolemic action of EGCG.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1244-1250
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• 1999

Job,s tears powder and green tea powder were added to bread mixture and their effects on the quality of bread were investigated using sensory evaluation and some physical tests. Sensory evaluation showed that flavor, hardness and chewiness were increased as the amount of Job's tears powder and green tea powder was increased. Lightness and redness values decreased with the addition of Job's tears powder and green tea powder, while yellowness values increased. Texture measurement showed that springiness was highest in bread with 3% green tea powder among the batches tested, while gumminess showed highest in control. Hardness of 3% green tea powder was lower than that of control. It appears that the higher the moistness, the higher the value of redness. Chewiness was positively correlated with yellowness. Gumminess was negatively correlated with color and flavor. Bread with 1% green tea powder and 10% Job's tears powder showed good overall preference. Scanning electron microscopy revealed that the addition of Job's tears powder and green tea powder to bread exhibited small pores and crude surface.