• The Korean Journal of Food And Nutrition
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• v.16 no.4
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• pp.365-371
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• 2003

This study was analyzed to the characteristics of the Lindera obtusiloba eaf teas by various manufacture methods. Moisture content was the highest in the tea processed by air dry method, and the lowest in the tea roasted after steaming. The contents of soluble solid was higher in the fermented tea than in the others, and the lowest in the roasted tea. The content of tannin was the higher in the roasted after steaming tea than in the others, and the lowest in the fermented tea. The content of vitamin C was the higher in the roasted tea than in the others, and the lower in the steamed tea. The mineral contents of leaf teas was orderly K, Na, Mn, Ca, Fe, Mg, and Zn. The roasted after steaming tea was estimated to the most excellent in the sensory evaluation of leaf teas.

• Journal of the East Asian Society of Dietary Life
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• v.16 no.5
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• pp.550-558
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• 2006

The study investigated the serum lipid metabolism and enzyme activities of Korean teas for their preventative activity against chronic disease and obesity. Male Sprague-Dawley rats were raised for 8 weeks on four experimental diets: normal diet, hyperlipidemic diet, and hyperlipidemic diet to which green and black teas (2% each) were added. Various biological actions, including lipid metabolism and enzyme activities of the serum, were investigated. Diet-induced, hyperlipidemic rats fed with green and black teas, showed significant decrease in food efficiency ratio, triglyceride, total lipid, and phospholipid compared to control, i.e. the normal and diet-induced, hyperlipidemic rats. Total cholesterol, LDL-cholesterol, Al(atherogenic index), LHR, VLDL-cholesterol, ester-cholesterol, and free-cholesterol also showed a significant decrease. However, there was no significant difference between the tea-fed, diet-induced, hyperlipidemic dieted groups. HDL-cholesterol concentration was increased significantly in the tea-dieted and normal groups compared to the control. There was a little difference in lipase activity between the normal and control groups, although green and black tea-dieted experimental groups were both increased compared to the control. The contents of total lipid, triglycerides, and total cholesterol were decreased in the normal and experimental groups compared to the control. The GOT, GPT, ALP and LDH serum enzyme activities of the experimental groups were significantly reduced compared to those of the control groups.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.1
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• pp.8-14
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• 2015

Livestock waste compost tea is a liquid extract of compost obtained by mixing livestock compost. In this study, some chemical and microbiological characteristics of compost tea depending on the kind of raw materials used were examined, and several experiments to investigate the practical effects on Chinese cabbage cultivation were conducted. This experiment showed that livestock composts needed to be added into aerated water at the ratio between 1:100 and 1:10 (1 part compost to 10~100 parts water) to produce the high quality compost tea. Compost teas must be aerated more than 24 to 48 hours to be able to support aerobic organisms. In cultivation test with compost teas, swine manure compost teas were made by the extracting ratio of 50x, in the aerated condition for 24 hours in water and oil cake in the extracting ratio of 100x were added as supplements. Following the input of oil cake, the concentration of nitrogen and aerobic bacteria increased. Another experiment was conducted to determine the effect of different swine manure compost teas on plant growth and yield of Chinese cabbage. The fresh yield of Chinese cabbage was higher in the fertigated plots by compost tea with oil cake compared to those of N, $P_2O_5$, $K_2O$ fertilization plot with chemical fertilizer by soil test recommendation (Fert. NPK). The effect of compost tea on growth of Chinese cabbage was largely attributable to the increased number of microorganisms as well as nutrients.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.33-38
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• 2010

This study was conducted to compare the physicochemical properties of powdered green teas produced in Korea and Japan including particle size, color, chlorophyll, caffeine and theanine. The average particle size of Korean powered green tea ($14.63-25.39\;{\mu}m$) was similar to that of Japanese powdered green tea ($15.46-21.02\;{\mu}m$). The surface color of shade-cultivated Haenam Green Tea (HN-1) had the highest negative 'a' value, which represents 'green' color. When the TCD (total color difference value) was measured in the samples, HN-1 was most similar to the premium powdered green tea of Japan (JA-1). Domestic shade-cultivated powdered green teas had 1.5-2 times greater chlorophyll content than powdered green teas produced from plants that were not cultivated in the shade. The presence of chlorophyll a resulted in a higher intensity of green color than the presence of chlorophyll b. A significant negative correlation was also observed between the color and the chlorophyll a, chlorophyll b and total chlorophyll contents. Specifically, chlorophyll a had the greatest impact on the green color of powdered green tea. The content of catechins, caffeine and theanine in Korean powdered green teas ranged from 14.679-20.128, 1.496-3.237 and 0.926-1.977 g/100 g, respectively. The caffeine and theanine contents were high in shade-cultivated powdered green teas. Based on the above results, domestic powdered green teas cultivated under shaded conditions had a quality similar to that of medium-quality green teas produced in Japan, and the overall quality of Korean powdered green tea was poorer than that of Japanese powdered green tea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.386-389
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• 1992

The four main tea catechin components (-)-epicatechin (EC), (-)-epigallocatechin (EGC) , (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gallate (EGCg) were analyzed quantitatively from commerical green teas by HPLC. CATechin of the most amounts in steamed and parched teas was EGcg (steamed 1st : 7.54% , parched 1st : 7.88%). Amounts of catechins decreased in the following order : EGCg > EGC>ECg>EC. Almost same tendency of catechin components change of 1st tea and 2nd tea differed to harvesting time being observed in steamed and parched teas. In 2nd tea, amounts of EGCg increased more than in 1st tea. It seems that this change effects on the quality of tea taste.

• The Korean Journal of Pesticide Science
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• v.17 no.1
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• pp.1-5
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• 2013

This study was conducted to the amount of pesticide residue in 21 different kinds of 100 commercial flowering teas. Multi-residue analyses of 203 pesticides was performed using the GC-ECD, GC-NPD, GC-MSD, and LC-MS/MS. Pesticide residues were detected in 4 samples (4%) of which 4 samples (4%) violated the maximum residue limits. 4 samples violating the limit were all imported teas. Pesticides detected were chlorpyrifos, flufenoxuron, lufenuron, pyrimethanil and methoxyfenozide. These results indicate the need of continuous monitoring of pesticide residue needs for safety of flowering teas.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.2
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• pp.263-268
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• 2003

This study was designed to test the effect of Korean traditional teas on lipid levels in lead (Pb)-administered rats. Male rats were divided into normal, Pb-control (rb-Con) and Pb-water extract of traditional teas (green tea: GWE, persimmon leaf: PWE, safflower seed: SWE, Solomon's seal: SSWE) groups. Pb intoxication was induced by administration lead acetate (25 mg/kg. BW, oral) weekly. The extract was administered based on 1.26 g of raw traditional tea/g BWday for 4 weeks. Net weight gain and feed intake were significantly lower in the Pb-Con group than in the normal group, whereas they were tended to increase by traditional teas supplements. Both Plasma and hepatic total cholesterol and triglyceride concentration were lower in the traditional teas supplemented groups compared to the Pb-Con group. Plasma VLDL-cholesterol and LDL-cholesterol levels were significantly increased by Pb ad-ministration, whereas HDL-cholesterol concentration was significantly lower in the Pb-Con group than in the normal group. However, water extracts of green tea, persimmon leaf, safflower seed and solomon's seal supplementation improved changes of the plasma lipoprotein-cholesterol levels in Pb administered rats.

• Journal of Convergence for Information Technology
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• v.11 no.3
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• pp.194-204
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• 2021

The reason why domestic fermented tea is less recognized than the world's top three black[Sri Lanka Uva black tea, India Darjeeling black tea, China Keemun(祁門) black tea] teas is that there is a very lack of scientific basis for clear quality standards and functionality. This researcher identified the major components of the world's top three black teas and fermented teas derived from domestic wild tea trees through analysis of various instruments such as HPLC, TOF-MS, and ELISA reader. In addition, in order to compare the physiological activity of the world's three major black teas and domestic fermented teas, the biological activity was compared and analyzed through DPPH·ABTS free radical scavenging activity and NO production inhibition. Furthermore, comparative analysis data on organic acid, free sugar, and tannic acid were obtained for quality comparison of palatable foods. When the above results are summarized, it is believed that it is possible to present the quality standards of Korean tea, and it is expected that the globalization of Korean tea will be possible.

• Bulletin of Food Technology
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• v.21 no.1
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• pp.22-24
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• 2008

• The Journal of Korean Medical History
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• v.20 no.1
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• pp.96-111
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• 2007

The tea culture is one of East Asia's traditional drink cultures and its variety, recipe, and effects are specifically recorded in East Asian documents. But the variety and applications of teas that are different from food and not entirely included in the medicine family has not been studied thoroughly yet. This study, through extracting and organizing the variety of teas and their recipes, aims to revive the methods of improving health by using ancient tea.