• Title/Summary/Keyword: Green tea leaf

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Antioxidant Activity of Herbal Teas Available on the Korean Market

  • Takako;Lee, Kyeoung-Im;Hiroshi Kashiwagi;Cho, Eun-Ju;Chung, Hae-Young
    • Preventive Nutrition and Food Science
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    • v.4 no.2
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    • pp.92-96
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    • 1999
  • The effects of aqueous extracts from Korean commercial teas on excessive free radicals were examined utilizing spin trapping, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical and lipid peroxidation. A potent scavenging effect of green tea and oriental senna tea was dound using sipin trapping. The most effective teasagainst the DPPH radical was green tea, followed inorder by pine leak tea, Chinese gutta percha tea and orietnal senna tea. Similar to the effects of DPPH radical , green tea, pine leaf tea, Chinese gutta percha tea and oriential senna tea had an inhibitory effect on lipid peroxidation. These findings predict that Korean tea is a promising material for scavenging free radicals, and for curing diseases related to free-radical reactions.

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The Effect of Plant Ethanolic Extracts on Oxidation of Soybean Oil (다류원류 식물류의 에탄올 추출물이 대두유의 산화에 미치는 영향)

  • 김미혜;김명철;박종석;박은지;김종욱;송경희;신동우;목진민;이종옥
    • Journal of Nutrition and Health
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    • v.31 no.8
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    • pp.1355-1364
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    • 1998
  • This study was planned to investigate the effect of 40 plant ethanolic extracts on antioxidant activities in vitro. The total phenolics, $\beta$-carotene, $\alpha$-tocopherol and selenium contents were also determined . Antioxidant activities fo the ethanolic extracts(0.02%, w/w) in the soybean oil were measured both by determining the peroxide value (POV) during 35 days of storage at 4$0^{\circ}C$ in a forced draft air-incubator and by determining changes in conductivity at 11$0^{\circ}C$(Rancimat method.). Soybean oil without any additives was used as a control and that treated with 0.02% BHT was used as a positive control. Based on the POV determination, green tea extract was found to be the most effective in stabilizing soybean oil, then followed by long tea, which both of them showed higher antioxidant activities compared to the BHT treatment. The antioxidant activities of them showed higher antioxidant activities compared to the BHT treatment. the antioxidant activities of coffee, cinnamomi cortex, acanthopanacis cortex, black tea, orange peel , instant coffee, peony and crni fructus extracts were stronger compared to the control .By the Rancimat method, green tea leaf and oolong tea leaf, foxglove, acanthopanacis cortex and peony extracts. Compared to other extracts, green tea leaf, black tea leaf, foxglove, acanthopanacis cortex and peony extracts had stronger antioxidative effects in both the POV and Rancimat methods used in this study. ethanolic extracts which showed the stronger antioxidative effect also has the higher contents of total phenolics, $\beta$-carotene, and/or $\alpha$-tocopherol. The antioxidative effect of ethanolic extracts was found to be due to the combined effect of various antioxidants.

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Effects of Green Tea, Buckwheat and Grape Leaves Extracts on Lipid Metabolism, Antioxidative Capacity, and Antithrombotic Activity in Rats Fed High Cholesterol Diets (녹차, 메밀, 포도잎 추출물이 고콜레스테롤 급여 흰쥐의 지질대사, TBARS 및 혈액응고에 미치는 영향)

  • Kim, Young-Eon;Oh, Se-Wook;Kwon, Eun-Kyung;Han, Dae-Seok;Kim, In-Ho;Lee, Chang-Ho
    • Korean Journal of Food Science and Technology
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    • v.36 no.6
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    • pp.979-985
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    • 2004
  • Effects of green tea, buckwheat, and grape leaf extracts on factors related to blood circulation were studied using rats fed high-cholesterol diet for 4 weeks. Rats were randomly divided into five groups, and plant extracts were orally administered. Green tea extract increased bleeding time in rat tails, suggesting it could prevent platelet aggregation. Administration of green tea, buckwheat, and grape leaf extracts decreased total cholesterol level in liver. Grape leaf extracts decreased thiobarbituric acid-reactive substances in plasma, whereas buckwheat and grape leaf extracts decreased the substances in liver. These results showed extracts of green tea, buckwheat, and grape leaf were effective for improving lipid composition in blood and liver and inhibiting lipid peroxidation in animal tissue, suggesting they may have potential to prevent cardiovascular diseases.

Effect of Green Tea and Lotus Leaf Boiled Water Extracts Treatment on Quality Characteristics in Salted Mackerel during Storage (녹차 및 연잎 열수추출물 처리가 염장고등어의 저장 중 품질특성에 미치는 영향)

  • Nam, Ki-Ho;Jang, Mi-Soon;Lee, Doo-Seog;Yoon, Ho-Dong;Park, Hee-Yeon
    • Food Science and Preservation
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    • v.18 no.5
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    • pp.643-650
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    • 2011
  • This study was carried out to analyze the quality change of mackerel treated of green tea and lotus leaf boiled water extracts. And investigate the antioxidant effects of them on the lipid peroxidation of mackerel during storage at $4^{\circ}C$ for 28 days. It was estimated periodical measurements of proximate composition, pH, carbonyl, volatile basic nitrogen, trimethylamine-N, acid, peroxide and thiobarbituric acid values. It had no effect on proximate composition compared with non- treated control nearly but, pH of all the samples was increase during 28 days continuously. The contents of volatile basic nitrogen and trimethylamine-N lower than control during storage. Also, acid, peroxide and thiobarbituric acid values of mackerel treated of green tea and lotus leaf boiled water extracts were significantly lower than control throughout storage period. Especially, mackerel treated of 2% green tea and lotus leaf boiled water extracts shows that more effective than 1% of things in antioxidant during storage. Results indicate that the application of green tea and lotus leaf boiled water extract on the surface of mackerel may be useful to lower the rancidity degree and fish odor during storage.

Changes of Some Chemical Compounds of Korean (Posong) Green Tea according to Harvest Periods (보성산 녹차의 채엽시기에 따른 화학 성분의 변화)

  • Kim, Sang-Hee;Han, Dae-Seok;Park, Jong-Dae
    • Korean Journal of Food Science and Technology
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    • v.36 no.4
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    • pp.542-546
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    • 2004
  • Changes in contents of catechins, caffeine, free amino acids, and minerals in green tea loaves according to harvest periods were compared. Total catechin content increased from 40.61 to 52.04 mg/g, while that of caffeine decreased from 17.56 to 14.61 mg/g according to harvest periods. Regardless of harvest periods, composition of catechins was epigallocatechin (EGC)>epigallocatechin gallate (EGCg)>epicatechin (EC)>gallocatechin (GC)>epicatechin gallate (ECg)>catechin (C)>gallocatechin gallate (GCg)>catechin gallate (Cg). Free amino acid content in green tea leaves was highest in young loaves, and gradually decreased according to harvest periods. Theanine content was markedly decreased with leaf aging, suggesting taste of green tea may be changed from mild to bitter with increasing harvest period. Analyses of mineral elements in green tea leaves showed that Fe, Mn, and Mg increased with leaf aging, while Cu showed opposite trend. Results reveal that content of some chemical compounds in Korean (Posong) green tea was highly dependent on harvest period.

Additive Effects of Green Tea on Fermented Juice of Epiphytic Lactic Acid Bacteria (FJLB) and the Fermentative Quality of Rhodesgrass Silage

  • Burrenok, Smerjai;Tamaki, Masanobu;Kawamoto, Yasuhiro;Nakada, Tadashi
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.6
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    • pp.920-924
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    • 2007
  • Two experiments were carried out on a laboratory scale. The first involved a study of the effect of green tea on characteristics of fermented juice of epiphytic lactic acid bacteria (FJLB). FJLB was treated with 50 g/L of green tea products as follows: new shoot powder (FJLB+N), leaf powder (FJLB+L), commercial powder (FJLB+P), sterilized new shoot powder (FJLB+SN), sterilized leaf powder (FJLB+SL) or sterilized commercial powder (FJLB+SP). FJLB without any additive was also prepared (Untreated FJLB). After incubation, the number of microorganisms in FJLB were studied. Subsequently, these FJLB were applied at 10 ml/kg to chopped rhodesgrass to study their effects on fermentation. Compared with untreated FJLB, the addition of green tea increased (p<0.05) lactic acid bacteria (LAB) and also aerobic bacteria counts in FJLB. At 60 d of ensiling, all the FJLB treated silages were well preserved, pH and butyric acid content were lower (p<0.001) and lactic acid was higher (p<0.001) than that of the control. Lactic acid content was significantly higher (p<0.001) with treated FJLB than with untreated FJLB. FJLB treated with sterilized green tea decreased (p<0.001) the pH and the lactic acid content was higher (p<0.001) than that in the unsterilized green tea silages.

Optimized Conditions for Making Tea from Camellia(Camellia japonica) Leaf and Flower and Sensory Evaluation

  • Kim, Ju-Hee;Im, Wha-Chun;Park, Min-Hee-;Lee, Jun-Ho;Lee, Sook-Young
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2003.10b
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    • pp.34-35
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    • 2003
  • Before making of tea, the number of leaf, plant height and node length in young shoot were 5.2, 14.9cm and 1,9cm respectively. These contents caused problems in leaf rolling and uniformity. No significant difference in quality and comoposition of roasted and steamed were observed, external shape and internal quality, however, were good from 1st to 3rd leaf. Chemical nutrition consists of leaf position, Total nitrogen content of terminal leaf was 4.88%, total free amino acid 21.12%, and caffein 3%. Vitamin C content was increased with increasing of leaf age. Making of roasted tea was required long time because camellia leaf was very hard and smoothly. Products had lower water color, perfume and taste. Internal quality of steamed tea was good in water color and taste. The contents of total nitrogen, total free amino acid, catechin, caffeine and vitamin C were 4.24%, 1.01, 17.7%, 2.6% and 75.7mg/ml.(중략)

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Fermentation Characteristics of Mustard Leaf Kimchi Added Green Tea and Pumpkin Powder (갓김치의 녹차 및 늙은호박분말 첨가에 따른 발효특성)

  • 한지숙;박민정;전영수
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.2
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    • pp.215-221
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    • 2001
  • Mustard leaf kimchi added different ratios of pumpkin powder(P) and green tea powder(G) were investigated by measuring changes of physicochemical, microbiological and sensory characteristics during fermentation at 5℃. The pH and total acidity were changed slowly until 20 days, and then changed rapidly for 20∼40 days in all mustard leaf kimchi groups. The pH and acidity of mustard leaf kimchi added 0.5% G was the most slowly changed compared to the other groups. Reducing sugar content was highest in mustard leaf kimchi added 0.5% P at early stage of fermentation, but the reduing sugar content of this mustard leaf kimchi group was decreased more rapidly than those of the other groups during fermentation. The numbers of lactic acid bacteria and total bacteria were highest in 0.5% P added group and lowest in 0.5% G added group. The mustard leaf kimchi added 0.3% P and 0.2% G was relatively high in number of Leuconostoc sp., on the contrary low in Lactobacillus sp. compared to the other groups during fermentation. Changes of Hunter's color values, especially yellowness, and hardness were smaller in each mustard leaf kimchi added 0.5% G, and 0.3% P and 0.2% G than the other groups. Sensory scores of taste, odor and overall acceptability were highest in mustard leaf kimchi added 0.3% P and 0.2% G. Based on these results, it is suggested that mustard leaf kimchi added 0.3% P and 0.2% G was the best group among mustard leaf kimchi groups.

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Variation in Chemical Components of Korean Green Tea (Camellia sinensis L.) Resulted from Developing Stages and Processing Recipe (한국산 녹차의 채엽시기 및 제조법에 따른 화학성분 변이)

  • Oh, Mi-Joung;Hong, Byung-Hee
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.40 no.4
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    • pp.518-524
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    • 1995
  • In this study physicochemical characteristics such as crude lipid, crude protein and total sugar contents have been analyzed with samples taken at different developing stages and growing sites, Bongsan-ri(steam-roasted green tea) and Buchun-ri(roasted green tea) area. Leaf area of new leaf was larger in Buchun-ri(7.23cm$^2$) than in Bongsan-ri(6.93cm$^2$). Variation of leaf area by the developing stages was the largest at between stage II (May 5) and stage III(May 18). Dry matters ratio of tea leaf were 26.3% in Bongsan-ri and 26.6% in Buchun-ri. Water content, ash, water-soluble matters, total sugar content of green tea sampled in Bongsan-ri and Buchun-ri were 5.6, 6.1, 33.1, 4.6 and 6.2, 5.8, 35.2, 2.8%, respectivley. Crude lipid, total nitrogen and water-soluble protein, inorganic matters content of green tea sampled in Bongsan-ri and Buchun-ri were 2.8, 5.1, 1.1, 2.56 and 2.2, 5.7, 1.0, 2.34%, respectively. At the later developing stages crude lipid, total sugar contents were increased, whereas total nitrogen had low content. Vitamin C, Vitamin E and Vitamin A content of green tea produced in Bongsan-ri and Buchun-ri area were 413mg%, 71.8mg%, 32.15IU and 311mg%, 52.3mg%, 25.68IU, respectively. Vitamin C and Vitamin E content were increased toward the later sampling stages. Water-soluble matters and water-soluble protein content of green tea prepared by the steam-roasted method and the roasted method were increased by 0.11, 0.13 and 0.09, 0.08%, respectively, compared to unroasted check. Crude lipid content of green tea prepared by the steam-roasted method and the roasted method were decreased by 0.13 and 0.24%, respectively. Total nitrogen content of green tea prepared by the steam-roasted method and the roasted method was changed 0.019 and 0.036%, respectively and total nitrogen content showed minute different between two methods.

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Development of a natural plant-nutrient from wasted tea leaves and stems

  • Kim, Jong-Cheol;Kim, Ru-Mi;Cho, Kyoung-Hwan;Kim, Yong-Duck;Hwang, Jung-Gyu;Han, Jae-Yoon;Lee, Jong-Gug
    • Korean Journal of Organic Agriculture
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    • v.19 no.spc
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    • pp.17-20
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    • 2011
  • Plant biomass is a huge carbon-complex that has potential as a nutrient. Therefore we extracted and separated useful materials for plant growth from tea leaf and stem. The pre-treatment process including high temperature ($200^{\circ}C$) and pressure (20-40 kgf/$cm^2$) was treated for several minutes and extracted at $120^{\circ}C$ for 30-60 minutes. After that the chemical compositions and ingredients were analyzed from that plant-nutrient. As a result of mineral contents, calcium and magnesium concentrations are higher than other minerals. Also the result of carbohydrates analyses has shown that the sugar oligomer consists of xylose(95.3%) and glucose(4.7%), and the sugar monomer consists in the order of xylose (52.7%) > manose (22.8%) > arabinose (10.8%) > galactose (10.2%) > glucose (3.5%). Before applied to field, in vitro plant growth system and formulation were examined. To evaluate the effect of the nutrients, both strawberry green-house and persimmon fields were used in this test. The treated persimmons were heavier than controls scored at 13-22%. In addition, the storage-period was extended in the treated strawberries. Interestingly in the treated strawberry, the contents of polyphenols were increased (38-57%). These results suggest that the plant-nutrient can afford to help for plant growth and storage, and it can be substituted for other commercial nutrients. In conclusion, this plant-nutrient may help to extend eco-friendly or organic farming in Hadong-gun area.