• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.144-149
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• 2004

Changes in functional constituents of grape (Vitis vinifera) seeds prepared by three different heat pretreatments were determined and compared with those of non-treated grape seed. The recovery of grape seed oils was generally increased by roasting, steaming and microwave processes, although the recovery of specific constituents varied among three heat pretreatments. The recovery of MeOH extracts of the seeds increased following the roasting process, whereas that of MeOH extracts decreased gradually with steaming and microwave treatments. Levels of four catechins in grape seeds: (+)-catechin, procyanidin B$_2$, (-)-epicatechin, and (-)-epicatechin gallate, were decreased with increased roasting and steaming time, but were unaffected by microwave treatment. During the three different heat pretreatments, levels and compositions of fatty acid did not change, whereas those of phytosterol compositions decreased greatly. These results suggest that a mild heat pretreatment, controlled for temperature and time, is needed to prevent a considerable loss in the level of valuable functional components in grape seed.

• KSBB Journal
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• v.23 no.1
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• pp.96-100
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• 2008

In this work, we describes analysis of the antioxidant potential of Korean green tea phenolics using an high-performance liquid chromatography (HPLC) on-line $ABTS^{+}$ antioxidant screening method. In conjunction with the analysis of their 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) radical scavenging ability, the extraction of catechine compounds from Korean green tea were performed by various temperature and time. The optimum operating conditions were experimentally determined to analyze the catechine compounds in the pretreatment extracts. From the results, the extraction temperature $60^{\circ}C$, time 3 min was selected as an optimal antioxidant activity condition. The analysis by $C_{18}$ column was performed, the flow rate of mobile phase and UV wavelength was fixed at 1.0 ml/min and 254 nm, respectively. the mobile phase was composed from acetonitrile and water, and the gradient elution mode were applied.

• Food Science of Animal Resources
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• v.18 no.4
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• pp.348-357
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• 1998

This study was conducted to investigate the effects of mugwort extracts on the blood ethanol concentration and liver function in rats. Sprague-Dawley rats were used, the rats administered with 25% ethanol (5g/kg$.$B.W.) were devided into three groups (CON-E ; 25% ethanol administered to the CON-E) according to the administered ethanol concentration and the levels of administered mugwonts. Mugwont roots extracts were administered via the caudal vein. Ethanol concentration was measured at the time of 0, 1, 2 and 3hr by gas chromatography. GOT(Glutamic Oxaloacetic Transaminase) and GPT(Glutamic Pyruvic Transaminase) were measured at the time of 0 and 5hr. Components of each extracts were analyzed by using high performance liquid chromatography. Cell number, GOT and GPT were investigated by using rat hepatocyte culture. Megwort extracts were added at the levels of 1% or 2%. Hepatocyte culture were into five groups according to the addition levels. The results were summarized as follows ; 1. Catechin contents of 8∼10mg/100g and the contents of (-)-epigallocatechin was high in the water extracts. 2. Ethanol degradation efficiency declines in the following order : MDW-E＞MOH-E＞CON-E. 3. The numbers of rat hepatocytes declines in the following order : 2% MDW-L＞1%MDW-L＞1%MOH-L＞CON-L＞2%MOH-L. These results suggest that crude catechin of mugwort extracts may play important roles to degrade ethanol and recover liver function in rats.

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.238-242
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• 1993

For the Purpose of utilizing tannins in the functional foods and crude drugs, the enzyme inhibition of tannins isolated from Korean green tea were determined. Acetone extract from Korean green tea showed inhibition effect against the angiotensin converting enzyme. The galloyl tannins showed higher inhibition activity against angioteosin converting enzyme than the nongalloyl tannins. In terms of stereo isomers, (-)-epicatechins had higher inhibition activity than the (+ )-catechins. The synergistic activity was also observed. Tannins isolated from Korean green tea appeared to be incompetitive inhibitor against the angiotensin converting enzyme.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.20-23
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• 1999

This study was conducted to investigate the content and composition of tea catechins at different plucking time and different position of tea leaves. The bud and first leaf, second leaf, third leaf, and fourth leaf were collected on May, July, and August. The catechin content was highest in leaves picked on August among those collected from different months. When compared with the different part of tea leaves, the bud and the first tea leaf contained the highest catechin, and the fourth left contained the lowest catechin. Analysis of catechin composition in the tea leaves, showed that epigallocatechin gallate was the highest, and the other contents were following order: epicatechin gallate, epicatechin, epigallocatechin.

• International Journal of Oral Biology
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• v.43 no.3
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• pp.123-127
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• 2018

Polyphenon 60 refers to the mixture of catechins present in green tea. The aim of this study was to investigate the antimicrobial activities of polyphenon 60 against 4 strains of Streptococcus mutans and 2 strains of Streptococcus sorbrinus, which are the major causative bacteria of dental caries. The minimum bactericidal concentration (MBC) values of polyphenon 60 for S. mutans and S. sobrinus were determined and the effect of biofilm formation inhibition of that was evaluated. The MBC value of polyphenon 60 against the bacterial strains was 2.5 mg/ml except for one particular strain, S. mutans KCOM 1128 for which the value was 1.25 mg/ml. The results of biofilm formation inhibition assay revealed that polyphenon 60 inhibited biofilm formation more than 90% at a concentration of 2.5 mg/ml. It was apparent that polyphenon exhibited biofilm formation inhibition activity along with bactericidal effect against S. mutans and S. sobrinus. Therefore, it is proposed that polyphenon 60 as one of the components of bactericidal agents could be useful in developing oral hygiene products, toothpaste or gargling solution.

• 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.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.1-6
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• 2003

Catechins exhibit a hypocholesterolemic effect in cholesterol-fed animals. The present study was conducted to examine whether (+)-catechin influences the absorption of cholesterol in rats. Male Sprague-Dawley rats were fed ad libitum an AIN-93G diet containing soybean oil for 5 wk. Rats with lymph cannulae were infused at 3.0 mL/h for 8 h via a duodenal catheter with a lipid emulsion containing radiolabeled cholesterol with or without (+)-catechin. Lymph was collected hourly for 8 h. The enteral infusion of (+)-catechin significantly lowered the lymphatic absorption of $^{14}$ C-cholesterol (21.1 $\pm$ 3.6% dose/B h) compared with controls infused with the lipid emulsion devoid of (+)-catechin (38.2 $\pm$ 1.2% dose/8 h). The intestinal absorption of $\alpha$-tocopherol (24.2$\pm$3.0% dose/8 h) also was significantly decreased by (+)-catechin infusion, relative to controls (32.2$\pm$2.2% dose/8 h). However, the lymphatic outputs of oleic acid and phospholipid were not affected by enteral (+)-catechin infusion. The results indicate that (+)-catechin has a profound inhibitory effect on the intestinal absorption of cholesterol and $\alpha$-tocopherol without affecting the absorption of fat.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.106-113
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• 2015

Effects of mineral salts (N, P, K, $Ca^{2+}$, $Mg^{2+}$, and $Fe^{3+}$) on the shoot growth and metabolite production of tea tree were studied using in vitro culture techniques. Among mineral s alts, ${H_2PO_4}^-$ was the most important for enhanced growth rate of tea tree, while $Mg^{2+}$ and $Ca^{2+}$ did not affect plant growth. Removal of ${NH_4}^+$ and $NO_3$ from the culture medium enhanced shoot multiplication compared to other treatments. Metabolite production was variable depending on mineral types and concentration. Removal of $Ca^{2+}$ decreased the production of caffeine; however, other treatments did not influence its production. $Ca^{2+}$, ${NH_4}^+$ and $Fe^{3+}$ were important factors for catechin production in tea tree. These results can be used as the basis for development of technical soil controls suitable for tea tree cultivation in the future.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.160-168
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• 1995

Desmutagenicities against 2-amino-1-methyl-6-phenylimidazo[4, 5-b] pyridine(PhIP) and 2-amino-3, 8-dimethylimidazo[4, 5-f]quinoxaline(MelQx) of tea extracts (steamed green tea, roasted green tea, oolong tea and black tea) were investigated. All the fractions obtained from tea extracts showed strong desmutagenic activity against PhIP and MeIQx toward S. typhimurium TA 98 in the presence of the S-9 mix. The crude catechin fraction exhibited the strongest desmutagenic activity. Among these tea extracts, black tea especially exhibited the strongest desmutagenic activity and the activity was 70.9~91.0% against PhIP and 92.2~98.8% against MelQx at a concentration(0.5~1.0mg/plate) for drinking. The activity of authentic catechins of (-)-EGC, (-)-EGCg, (-)-ECg and (-)-EC were 79.5%, 60.2%, 46.1% and 43.5% against PhIP, and were 52.3%, 11.6%, 8.2% and 22.1% against MelQx by addition of 1.0mg/plate, respectively. The desmutagenic activity was supposedly due to the (-)-EGCg, (-)-EGC and (-)-EC in tea polyphenols, and the browning materials. The desmutagenicity was stronger when mutagens were preincubated with S-9 mix after reaciton with black tea extracts than when preincubated with them after reaction with S-9 mix. The desmutagenicity of tea extracts was rather expressed by reacting directly with mutagens than by deactivating the activated forms of mutagens.