• 한국식품조리과학회지
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• 제31권5호
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• pp.581-587
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• 2015

This study was conducted to investigate the antioxidative and antimicrobial activities of Korean dandelion (Taraxacum coreanum). Water extracts, ethanol extracts and methanol extracts were used to examine the free radical scavenging activity, total flavonoid content, total polyphenol content and antimicrobial activity. The free radical scavenging activity, total flavonoid, total polyphenol and total antioxidant activity of the water extracts were higher than those of the other extraction solvents. The antimicrobial activties of Korean dandelion extracts were examined on several food borne illness microorganisms using the paper disc diffusion method. Inhibition zones were observed on Staphylococcus aureus subsp. aureus, Listeria monocytogenes, Bacillus subtilis, Bacillus cereus and Escherichia coli in ethanol extracts. Inhibition zones were also observed on Listeria monocytogenes in water extracts. The physico-chemical properties of Korean dandelion tea according to the roasting time and soaking amount of tea were studied. The pH of the dandelion tea significantly decreased while the soluble solid contents significantly increased with increased roasting time (p<0.01). The lightness of the dandelion tea decreased and the turbidity increased with increased roasting time. In sensory evaluation, the sensory scores for the color, flavor and total acceptability were highest in the 40 min roasted tea. These results suggest that the water extract of Korean dandelion could be used as an antioxidative and antimicrobial functional food source. The optimum roasting time for Korean dandelion tea was 40 min at $200^{\circ}C$.

• 한국식품영양과학회지
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• 제24권2호
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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.

• Archives of Pharmacal Research
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• 제29권9호
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• pp.786-794
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• 2006

We observed the suppressive effect of a powder formulation of African black tea extract prepared from the leaves of Camellia sinensis on type 2 non-insulin dependent diabetic mice, $KK-A^y/TaJcl$. Black tea extract significantly showed suppressive effect of the elevation of blood glucose on oral glucose tolerance test of 8 week-old $KK-A^y/TaJcl$ mice (p<0.05). Long-term treatment with black tea extract showed significant suppression of post-prandial blood glucose and obesity (p<0.05). The weight of the intestine of mice treated with black tea extract was significantly reduced (p<0.05). From these results, African black tea used in this study showed a suppressive effect on the elevation of blood glucose during food intake and the body weight.

• Food Science and Biotechnology
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• 제18권4호
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• pp.932-938
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• 2009

Browning of tea infusion is an obstructive factor influencing shelf life of ready-to-drink green tea. Effects of temperature and illumination on the browning of green tea infusion were investigated. It was shown that both elevated temperature and illumination led to the browning of green tea infusion, but temperature had greater effect on infusion color and level of catechins than illumination. The levels of unoxidized catechins such as (-)-epigallocatechin gallate (EGCg), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), (-)-epicatechin (EC), and total catechins remaining in the tea infusion were significantly correlated to color parameters of the tea infusion. Sodium ascorbate inhibited the infusion browning by suppressing the oxidation of tea catechins and it is considered to be a more suitable preservative for prolonging shelf life of ready-to-drink green tea than ascorbic acid because it has less effect on tea taste. The effects of temperature and illumination on the epimerization of catechins were also discussed.

• 한국식품영양과학회지
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• 제40권8호
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• pp.1073-1078
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• 2011

위생적으로 안전성이 확보된 후발효차를 제조하기 위해 Bacillus subtilis, Saccharomyces cerevisiae 및 Lactobacillus bulgaricus를 이용하여 후발효차를 제조한 후 발효시간에 따른 항산화 성분 및 활성의 변화를 측정하였다. 후발효차의 ascorbic acid의 함량은 발효기간 내내 균종에 관계없이 녹차(66.74 mg%)에 비하여 비교적 낮은 함량(43.62~62.84 mg%)을 보였고 산소와의 접촉을 최소화한 L. bulgaricus 균에 의한 발효가 비교적 적은 변화를 보였다. Polyphenol 화합물의 함량은 녹차의 경우 14.88%였으며 후발효차는 11.54~14.12%로 세 균주 모두 발효가 진행됨에 따라 함량이 다소 감소하였다. 실험에 사용한 녹차의 flavonoid 함량은 7.78 mg%였으며 미생물을 이용한 후발효차의 경우에는 4.33~7.88 mg%로 대부분 녹차에서의 함량보다 적은 것으로 나타났다. 항산화 활성의 경우, 녹차의 DPPH 전자공여능 및 ABTS 항산화 활성은 각각 87.47% 및 203.22 AEAC mg%였으나 발효기간에 따른 후발효차에서는 녹차에 비하여는 낮은 활성을 보여 후발효차 제조 시 어느 정도 항산화 성분의 함량 및 활성이 다소 감소하게 되지만 미생물을 이용하여 후발효차를 제조 시 위생적이고 기호도가 우수한 제품을 생산할 수 있는 것으로 판단되었다.

• 원예과학기술지
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• 제35권2호
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• pp.252-264
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• 2017

Tea is one of the most consumed beverages worldwide and the relatively high levels polyphenols is benefit for health. In this study, we developed an efficient system for proliferation of callus from 'Anji Baicha', a cultivar of tea (Camellia sinensis). Callus tissue was initially induced by culturing leaf explants on medium containing different plant growth regulators. For callus induction, thidiazuron (TDZ) was more effective than 2,4-dichlorophenoxyacetic acid (2,4-D), ${\alpha}-naphthalene$ acetic acid (NAA), and $N^6-benzyladenine$ (BA). The frequency of callus induction from leaf explants reached 90.21% on $1.0mg{\cdot}L^{-1}$ TDZ and the developed callus was reddish and friable. We also tested the effect of different concentrations of NAA, 2,4-D, indole 3-acetic acid (IAA), BA, and TDZ, alone and in combinations, on callus proliferation. Medium supplemented with TDZ in combination with IAA was suitable for callus proliferation and accumulation of tea polyphenols. The growth index value and tea polyphenol content of callus cultured on MS medium containing $0.5mg{\cdot}L^{-1}$ TDZ and $1.0mg{\cdot}L^{-1}$ IAA was maximally 1,351% and 23.24%, respectively, and the relative abundance of epicatechin was as high as 17.449%. We also measured the antioxidant activity of all samples and the callus with the highest tea polyphenol content also exhibited high potential radical scavenging activity.

• Journal of Applied Biological Chemistry
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• 제55권1호
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• pp.19-25
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• 2012

Green tea leaves were fermented for 15 and 30 days with Monascus pilosus which is known to produce functional statins (TMs), and the content of various biochemical constituents such as total polyphenol (TP), total flavonoid (TF), theaflavin, and thearubigin were analyzed and compared with that of non-fermented green tea (GT) and Pu-erh Chinese post-fermented tea (PU). In addition to the electron donating ability (EDA), ferric iron reducing power (FIRP), xanthine oxidase (XO) inhibitory activity, superoxide dismutase (SOD)-like activity, iron chelating activity (ICA) and hydrogen peroxide contents were also measured and compared with that of GT and PU. Content of TP and TF in the water and ethanol extracts in TMs were lower than those in GT and PU. Theaflavin and thearubigin contents of water and ethanol extracts in TMs were higher than those of GT. And, these components were increased depending on the period of fermentation. While, EDA and FIRP of TMs were lower than those of GT, XO inhibitory activity of TMs was higher than non-fermented tea. While, ICA of TMs was slightly higher than GT and PU, the content of hydrogen peroxide in TMs was markedly lower than GT. This results suggested that the green tea fermented by M. pilosus was valuable for oxidative stress-induced diseases by decreasing hydrogen peroxide, and forming theaflavins and thearubigins with functionality of genus Monascus.

• KSBB Journal
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• 제23권5호
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• pp.387-391
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• 2008

본 연구에서는 건조된 녹차 뿌리와 씨에 함유된 성분중에서 무기성분, 비타민, 총 아미노산과 유리 아미노산, 총 폴리페놀 및 그 구성 성분들의 함량을 분석하였다. 뿌리와 씨의 무기성분 중에서는 K의 함량이 각각 1,052 mg/100 g과 1,480 mg/100 g으로 가장 많았고, 뿌리에서 P, Ca, Mg, Na, Fe, Mn, Zn, Cu의 순으로, 씨에서는 P, Na, Ca, Mg, Mn, Fe, Cu, Zn의 순으로 함량이 많았다. 뿌리에서 vitamin C의 함량은 5.72 mg/100 g으로 가장 많았고 씨에서는 6.05 mg/100 g으로 나타났다. 비타민의 함량을 살펴 본 결과 녹차 뿌리보다 씨에 더욱 많은 종류의 vitamin이 함유되어 있었고 그 함량도 뿌리에 비해 다소 높은 경향이었다. 총 아미노산은 뿌리에 1,651 mg/100 g, 씨에 4,335 mg/100 g 함유되어 있어 각국 시판 녹차에 비해 그 함량이 높았고, 녹차에서 존재하지 않는 아미노산인 phenylalanine도 16.00 mg/100 g와 139.00 mg/100 g 존재하는 것으로 나타났다. 유리 아미노산의 경우, 뿌리에서 녹차의 품질을 평가하는 theanine이 전체 유리 아미노산 함량의 48%를 차지하였고 쓴맛을 내는 arginine, valine 및 tryptophan 등의 함량이 높았으며, 열매에서는 단맛과 감칠맛을 내는 glutamic acid, alanine, theanine, aspartic acid 및 serine 등의 함량이 많았다. 총 polyphenol은 뿌리에 237 mg/100 g으로 씨에서의 함량 81 mg/100 g보다 3배가량 높았다. Polyphenol 중 catechin의 함량은 뿌리에서 66 mg/100 g, 씨에서 1 mg/100 g으로 나타났고 caffeic acid는 뿌리에서 0.78 mg/100 g으로 나타났지만 씨에서는 검출되지 않았다. 또한 chlorogenic acid는 뿌리와 씨에서 각각 3.7 mg/100 g과 6.6 mg/100 g 검출되었다.

• 한국식품저장유통학회지
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• 제13권5호
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• pp.596-602
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• 2006

본 연구는 한지역에서 생산된 동종의 차 엽을 같은 시기에 채취하여 불발효차와 반발효차로 발효정도가 다르게 제다하여 주요 성분과 생리활성을 비교하였다. 불발효차인 녹차는 일반 가공 방식대로 만든 녹차, 채엽하여 실내 위조의 과정을 거쳐서 만든 위조 녹차로 만들었고, 반발효차인 황차는 햇볕에서 제다한 중(中)발효차인 일쇄차와 강하게 발효를 한 황차를 시료로 하였다. 주요 성분은 일반성분 및 폴리페놀과 카페인의 함량을 분석하였고, 차의 수색,전자공여능에 의한 항산화 활성 및 ACE 저해능을 조사하였다. 결과는 다음과 같다. 차의 일반성분은 발효정도와 제다방법에 따라 큰 차이는 없는 것으로 나타났다. 차의 기능성분을 조사해 본 결과 total phenolic compound 함량은 $3.59%{\sim}3.87%$의 범위로 나타나 발효정도와 제다방법에 따라 큰 차이는 없는 것으로 나타났다. 반면 caffeine 함량은 녹차가 5.81%로 가장 높았으며, 위조차가 5.75%, 일쇄차가 3.46%, 황차가 2.66% 순으로 발효정도에 따라 caffeine 함량이 감소하는 경향을 보였다. 차의 수색은 발효정도가 강할수록 명도(L)는 감소하였고, 녹색도(-a)가 낮아지면서 적색(a)에 가까워졌으며, 황색도(b)는 발효정도에 따라 높아지는 경향을 보였다. 차의 전자공여능에 의한 항산화 활성은 녹차가 85.6%로 가장 높았으며, 위조차가 81.24%, 일쇄차가 72.84%, 황차가 28.85% 의 순으로 불발효차 일수록 항산화활성이 뛰어났으며 ACE 효소 활성 역시 불발효차 일수록 증가하는 경향을 보였지만 그 차이는 미비하였다.

• 한국식품과학회지
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• 제35권6호
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• pp.1199-1203
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• 2003

한국산 녹차를 70% 에탄올로 추출한 후 Sephadex LH-20과 HPLC를 사용하여 polyphenol을 분리동정하였고 분리된 각 성분들의 angiotensin converting enzyme(ACE) 및 xanthine oxidase, tyrosinase의 저해효과를 확인하였다. 녹차로부터 HPLC로 polyphenol을 분리한 결과 epiafzelechin-$(4{\beta}{\rightarrow}8)$-epiafzelechin, procyanidin B-3-3-O-rhamnose, afzelechin-$(4{\alpha}{\rightarrow}8)$-catechin, prodelphinidin B-5-3,3'-di-O-digallate, (+)-taxifolin-3-O-D-xyloside 등 11종류를 분리하였다. ACE의 저해효과는 prodelphinidin-C-2-3,3'-di-O-gallate $100{\mu}M$에서 68.8%, procyanidin B-2-3,3'-digallate가 54.6%의 저해를 나타내었고, Xanthine oxidase는 prodelphinidin C-2-3,3'-di-O-gallate가 54.5%, procyanidin B-2-3,3'-digallate가 38.2%로 높은 저해효과를 보였다. Tyrosinase의 저해효과는 $100{\mu}M$ 농도에서 prodelphinidin C-2-3,3'-di-O-gallate가 42.1%, procyanidin B-2-3,3'-digallate와 procyanidin B-7이 각각 30.7%, 20.5%의 저해를 나타내었다. 따라서 녹차 추출물로부터 분리한 polyphenol이 혈압예방, 통풍 및 미백효과의 기능성 식품 신소재로서 이용이 가능하다는 것을 확인하였다.