• 한국식품영양과학회지
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• 제28권1호
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• pp.100-106
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• 1999

Use of chemical preservative for controlling harmful microorganisms in food products has been debated due to public concerns about food quality because of perceived toxic and carcinogenic potential. Thus, use of non toxic natural antimicrobial agents has become essential. This study was investigated to determine the antimicrobial activity of water or ethanol extract of commercially available tea, and of solvent fractionated ethanol extracts obtained from steamed green tea. Both of water and ethanol extracts of green tea(steamed or roasted), oolong tea and black tea exhibited strong antimicrobial activity against gram positive and negative bacteria, but not effective against yeast and mold. Also, antimicrobial activity of ethanol extract of 4 different kinds of tea was stronger than that of water extract. Among 4 different tea, ethanol extract of steamed green tea was further fractionated. One thousand g/disk buthanol extract had the strongest antimicrobial activity against bacteria and mold. The concentration of the antimicrobial activity of buthanol extract in tested microorganisms ranged from 125~1000 g/disk except for Rhizopus javanicus. Antimicrobial activity of buthanol extract of steamed green tea was not destroyed by heating at 100oC for 60 min and at 121oC for 15 min, which is very stable over heat treatment. The inhibitory effect of the buthanol extract on the growth of Listeria monocytogenes and Staphylococcus aureus was investigated. Growth of both strains was started in the presence of 250 and 500 g/ml after 12 and 24 hour respectively, whereas complete inactivation of both strains was occurred in the presence of 1000 g/ml.

• Food Science and Biotechnology
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• 제16권1호
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• pp.167-170
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• 2007

(-)-Epigallocatechin-3-gallate (EGCG), a mai or tea catechin has been shown to have many interesting biological activities. In the present study, we studied the effects of green tea catechins, EGCG metabolites, and black tea theaflavins on accumulation of EGCG in HT-29 human colon cells. Intracellular levels of [$^3H$]-EGCG were not changed significantly in the presence of other tea catechins including (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin-3-gallate. EGCG methyl metabolites and EGCG 4"-glucuronide did not affect cellular levels of [$^3H$]-EGCG. Black tea theaflavins and theasinensin A (TsA), an EGCG oxidative dimer, however, significantly decreased cellular accumulation of EGCG in HT-29 cells by 31-56%. This decrease was more pronounced when cells were incubated in the presence of theaflavin-3',3"-digallate (TFdiG) or TsA. When EGCG was added separately from TFdiG or TsA, the accumulation of EGCG in HT-29 cells was also significantly decreased regardless of when TFdiG or TsA was added during the uptake study (p<0.01). The results suggest that theaflavins and TsA may interrupt EGCG absorption through the gastrointestinal epithelium.

• Applied Biological Chemistry
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• 제48권4호
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• pp.375-381
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• 2005

본 연구는 흰쥐와 과체중인에서 솔잎, 홍차 및 녹차 추출물의 항-비만효과와 관련기전을 알아보기 위하여 시행되었다. 흰쥐는 무작위로 솔잎, 홍차, 녹차 및 추출물 혼합물 군으로 분류되었다. 대조군은 흰쥐 chow 식이로 사육되었으며 추출물군은 각각 0.5, 1, 2, 4 및 8% 추출물을 흰쥐 chow 식이에 첨가하여 5주간 사육하였다. 추출물 혼합물은 솔잎 :홍차 :녹차를 2 : 1 : 1의 비율로 만들어 흰쥐 chow 식이에 첨가하여 제조하였다. 솔잎과 혼합물 추출물 1, 2, 4 및 8% 첨가군은 대조군에 비하여 유의하게 체중과 내장지방을 감소시켰다. 홍차와 녹차추출물 1, 2, 4% 첨가군은 대조군에 비하여 유의하게 체중과 내장지방을 감소시켰다. 추출물 혼합군이 다른 군에 비해서 체중과 내장지방 감소효과가 컸다. 5주간의 식이동안 총 식이 섭취량은 녹차 및 홍차 8% 첨가군을 제외하고는 그룹간 차이가 없었다. 5주간의 식이에서 총 변량은 솔잎, 녹차 및 추출물 혼합 1, 2, 4% 첨가군에서 대조군보다 많았다. 과체중인에서는 추출물 혼합물이 대조군에 비하여 체중과 체지방을 유의하게 감소시켰다. 솔잎, 홍차 및 녹차의 작용기전을 알아보기 위한 시험관실험에서 솔잎은 췌장의 lipase 및 ${\alpha}-amylase$ 활성도를 억제하지 않았다. 반면에 홍차와 녹차는 농도 의존적으로 췌장의 lipase 및 ${\alpha}-amylase$ 활성도를 억제하였다. ${\alpha}-amylase$의 억제효과는 홍차가 녹차보다 컸으나 lipase의 활성 억제는 반대였다. 결론적으로 흰쥐에서 솔잎, 홍차 및 녹차의 항-비만 효과가 관찰되었으며 추출물 혼합물의 항-비만 효과가 같은 조건에서는 가장 컸다. 과체중인에서 추출물 혼합물은 대조군에 비하여 체중 및 체지방 감소효과를 보였다. 홍차와 녹차의 항-비만효과는 부분적으로는 위장관에서 췌장 lipase와 ${\alpha}-amylase$의 활성 억제에 의한 탄수화물과 지방의 소화감소에 기인하는 것으로 생각된다.

• The Plant Pathology Journal
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• 제17권6호
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• pp.350-353
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• 2001

In 2001, a black scab disease was observed in tea plant (Thea sinensis) cultivated in the hillsides of Hwngaemyon and Hadong-gun, Gyeongnam province, Korea. The disease symptoms initially appeared on leaves, green twigs and stems, showing small dark brown spots on the infected areas, which gradually expanded. A fungus was isolated from diseased leaves and green twigs. It grew readily on potato dextrose agar, forming dark green to dark gray colonies. The optimum temperature for mycelial growth was about 20$^{\circ}C$. The diameter of growing hyphae was 3.5-5.8 $\mu\textrm{m}$. Conidia were ellipsoidal, ovoid or subspherical, and mostly one-celled but occasionally septate. The size of one-celled and septate conidia were 3.7-12.4${\times}$3.4-5.2 $\mu\textrm{m}$ and 9.3-18.7${\times}$3.8-7.2 $\mu\textrm{m}$, respectively. Conidia were formed in long branched chains on the erected conidiophores, which were dark brown in color and 28.9-218.3${\times}$3.0-6.1 $\mu\textrm{m}$ in length. The fungus was identified as Cladosporium herbarum on the basis of its morphological characteristics. The black scab disease occurring in tea caused by Cladosporium herbarum has not been previously reported in Korea.

• 한국식품과학회지
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• 제31권2호
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• pp.273-279
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• 1999

국내외에서 재배, 유통되고 있는 다류소재 식물류 40종에 대하여 총 페놀성 물질과 비타민 C 함량은 비색법으로, ${\alpha}-tocopherol$과 ${\beta}-carotene$ 함량은 HPLC에 의해, 셀레늄 함량은 원자흡광법을 이용하여 분석하였다. 시료 100 g당(건량) 들어있는 총 페놀성 물질 함량은 녹차잎, 홍차잎, 우롱차잎, 인스탄트커피 등이 약 7g으로 가장 높았고 셀레늄 함량은 산수유와 칡이 약 $4{\mu}g$으로 가장 높았다. ${\beta}-carotene$ 함량은 두충$(8587{\mu}g)$, 감잎$(6222{\mu}g)$, 녹차잎$(3652{\mu}g)$ 등이 매우 높았다. ${\alpha}-tocopherol$ 함량은 감잎(33 mg), 두충(26 mg), 녹차잎(16 mg), 홍차잎(13 mg) 순으로 높았으며, 비타민 C 함량은 녹차잎(199 mg)과 홍차잎(117 mg)이 가장 높았다.

• Journal of Nutrition and Health
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• 제31권8호
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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.

• Archives of Pharmacal Research
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• 제21권3호
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• pp.348-352
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• 1998

Different bacteria wwere seperated from saliva and teeth of cariogenic patients and identified by a variety of morphological and biochemical tests. Extracts of green tea strongly inhibited Escherichia coli, Streptococcus salivarius and Streptococcus mutans. The antibacterial effect of green and black tea extracts were compared with those of amoxicillin, cephradine and eugenol.

• 한국의류산업학회지
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• 제8권3호
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• pp.343-348
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• 2006

This study aims to attain gray tone dyed goods by using tannin that is contained in green tea. Tannin is given general name of polyphenol, which has a characteristic that bonds with protein and it is used for food preservative that protects against bacteria, as well as its purpose of black tone dye for silk treatment that has been processed since its early ages. In particular, as tannin reacts with all kinds of metallic mordant and changes to various colors, when tannin acid is combined with iron, it becomes tannin steel and produces gray tone color. Tannin that is contained in green tea is condensed tannins and its structure does not hydrolyze, thus having flavan type structure. In order to find the suitable condition for processing tannin, UV-Vis part absorption spectrum of green tea tannin, dye ability based on temperature and time, reflection rate based on concentration, color changes based on acid treatment and alkali treatment, changes on surface based on concentration or metal mordant condition, and lightfastness were measured. Maximum absorption wavelength (${\lambda}_{max}$) of green tea tannin was at around 273nm, while strong absorption was also observed at below 350 nm. Dye ability of green tea tannin is done more easily on silk rather than cellulose fibers such as cotton, while the optimum condition for dyeing was observed to be at $60^{\circ}C$, for 20 minutes. As a result of acid treatment, the color of dye material consisted highly of gray tones and showed overall gray tone with the combined color of yellow and red after the alkali treatment. While it was observed that as dye concentration and metal mordant concentration increased, the color changed at counter-clockwise direction on the Y-scale of Munsell's scale of colors. Additionally, lightfastness was more on a normal fading.

• 한국식품영양과학회지
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• 제32권3호
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• pp.356-362
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• 2003

녹차와 발효시 간을 각각 다르게 하여 제조한 약발효차(10시간 발효), 중발효차(17시간 발효), 강발효차(24시간 발효)에 대한 이화학적 특성을 분석한 결과는 다음과 같다. 녹차 및 발효된 차의 수분 함량은 3.01 ~ 3.29%로 나타났고, 환원당 ,조지방, 조단백질 함랑은 발효를 많이 시킨 차일수록 증가한 반면, ascorbic acid는 감소하였다. 차의 유리당은 glucose, fructose, sucrose 등 3개의 당이 확인되었으며, 유리당의 총 함량은 녹차가 3.08%, 강발효차가 3.32%로 발효를 많이 시킨 차일수록 약간 증가하는 경 향을 나타냈다. 차의 유기산은 citric acid, malic acid, succinic acid 등 3개의 산이 확인되었고 citric acid와 malic acid 함량은 발효를 많이 시킨 차일수록 함량이 증가하는 반면, succinic acid 함량은 감소하는 경향을 나타냈으며, 유기산의 총함량은 발효를 많이 시킨 차일수록 대체로 증가하는 경향을 나타냈다. 차에 함유된 유리 아미노산은 AsP 외 16종이 확인되었다. 유리 아미노산의 총함량은 발효를 많이 시킨 차일수록 증가하는 향을 나타내었다. 녹차와 각 발효차의 주요 아미노산은 Thr+theanine, Asp, Glu으로 나타났으며, 녹차는 Thr+theanine, Asp, Glu 순으로 높게 나타났고, 발효차는 Thr+theanine, Glu, Asp 순으로 높게 나타났다. 유리아미노산의 총함량에서 필수아미노산이 차지하는 비율은 발효를 많이 시킨 차일수록 증가하는 경향을 나타냈다. 녹차에 함유된 theanine 함량은 1.21%였으며, 중발효차와 강발효차는 각각 1.42%, 1.50%로 녹차에 비하여 theanine 함량이 증가되었다. Caffein 함량은 비발효차인 녹차의 경우 3.57%, 발효된 차는 3.55~3.60%로 발효에 따른 변화는 거의 없었다. Cathechin은 5종류의 cathechin, epig-allocathechin, epicathechin, epigallocathechingallate, epicathechin gallate이 동정되었으며, 녹차의 카테친 함량이 14.18%로 높고, 발효를 많이 시킨 차일수록 현저하게 감소하였다.

• 한국식품과학회지
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• 제38권1호
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• pp.5-9
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• 2006

본 연구는 차에 함유되어 있는 특유의 정미성분으로 methylxantin류, catechin류 및 theaflavin류의 총 13종의 화합물을 HPLC를 이용한 동시분석법을 확립함과 동시에 이 분석법을 이용하여 한국에서 사판되고 있는 녹차, 홍차 및 우롱차에 함유되어 있는 주요 성분을 분석하였으며 그 결과는 다음과 같다. HPLC분석조건은 역상(ODS)column을 이용하여 acetonitrile: 20 mM 인산완충액의 solvent 중 acetonitrile의 농도를 처음 단계 7%에서 최종 40%까지 단계적으로 변화시켜 분당 1mL씩 용출시켜 분석하였다. Column 온도는 효과적으로 각 성분을 분리시키기 위하여 정확하게 $30^{\circ}C$로 설정하였으며 파장은 270 nm에서 분석하였다. 또한 차에 함유되어 있는 methylxantin류, catechin류 및 theaflavin류의 총 13종의 화합물을 분석한 결과, 한 시료당 90분이 소요되었으며 재현성과 정량성이 뛰어나 13종의 화합물이 완전하게 분리되었다. 시판 녹차, 홍차, 우롱차를 분석한 결과, 녹차와 우롱차는 2종류의 methylxantin류와 7종류의 catechin류는 검출되었으나 홍차에서 검출된 4종류의 theaflavin류는 전혀 나타나지 않았다. 이러한 결과는 차의 품질 관리 및 소비자의 차 선택에 있어 중요한 기초자료가 될 것으로 사료된다.