• Journal of Food Hygiene and Safety
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• v.31 no.2
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• pp.132-139
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• 2016

The purpose of this study was to investigate the contents of antioxidant compounds and antioxidant activities in teas. A total of 99 teas were tested for their antioxidant activities based on their ability to scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical. Antioxidant activity was expressed as mg of ascorbic acid equivalents per 100 g tea sample (L-ascorbic acid equivalent antioxidant capacity, AEAC) and was expressed as mg per 1 serving size (free radical scavenging activity, $FSC_{50}$). The total polyphenol contents of the extracts was quantified using the Folin-Ciocalteu method and the total flavonoid contents of the extracts was determined using a modied method of Davis. Vitamin C was analyzed by HPLC method. According to the AEAC value, mate tea, green tea, black tea, oriental raisin tea, chamomile tea and burdock tea showed relatively high antioxidant activities. Polyphenolic compounds were the major naturally occurring antioxidant compounds found in teas and the high concentrations of total polyphenol compounds were observed in black tea, green tea and mate tea. The high concentrations of total flavonoid compounds were observed in mate tea, black tea and yam tea and the amount of vitamin C contents were found to be high in citron tea and green tea. As a result, steeping tea was much higher in antioxidant activity than either powdered tea or liquefied tea. According to the study, a high correlation was demonstrated between the total polyphenol contents and antioxidant activities in teas (r = 0.846) and correlations between the total flavonoid contents and antioxidant activities was statistically significant in teas (r = 0.625). It was found that also the proportional relationship established among the total polyphenol content and antioxidant activities. That is, antioxidant activity of teas has been confirmed to have been caused by the total polyphenol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.4
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• pp.316-322
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• 1983

In order to obtain elementary data of enzymatic browning of apples and apple products and to examine effectively inhibitory method of browning, we extracted polyphenol oxidase (EC 1.10.3.1) from apple (Ralls Janet) and investigated its general properties. The optimum conditions for the enzyme reaction were pH 6.0 and temperature of $30^{\circ}C$. The enzyme was very stable at pH 4.0, and at the range of pH 5.0-9.0 its activity was above 80% compared with pH 4.0. The enzyme was very stable by heating at $40^{\circ}C$ for 1 hour, and almost 50% of enzyme activity was lost by heating at $60^{\circ}C$ for 30 minutes. The polyphenol oxidase activity was enhanced by the addition of $Cu^{2+}$ and $Mn^{2+}$, respectively, meanwhile $Na^+$, $Hg^{2+}$ and $Co^{2+}$ inhibited the enzyme activity. The enzyme activity was greatly decreased in the presence of inhibitors such as cysteine, sodium metabisulfite and ascorbic acid. The polyphenol oxidase greatly catalyzed the oxidation of o-diphenols such as chlorogenic acid and catechol, which suggests that main substrate of polyphenol oxidase is o-diphenol compounds.

• Microbiology and Biotechnology Letters
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• v.43 no.2
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• pp.97-104
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• 2015

Vinegar is a widely used acidic seasoning and can be manufactured using various methods and bases, including cereals, wheat, and fruits. Most studies on vinegar have been conducted to evaluate its antioxidant activity. In the present study, fermented dark vinegar (FDV) produced from unpolished rice was examined for its antimicrobial activity, biochemical content, including the amounts of sugar, total soluble sugar, organic acid, and free amino acids, and pH and physiological activity. The antimicrobial efficiency of FDV was assessed using the paper disc-agar diffusion method. FDV exhibited strong antimicrobial activity against the pathogenic bacteria and yeast strains that were tested. In fact, the activity of FDV was shown to be higher than that of the commercial antibiotics carbenicillin (50 µg/ml) and tetracycline (50 µg/ml) against Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Yersinia enterocolitica, and Lodderomyces elongisporus. The antioxidant activity of FDV and ascorbic acid was evaluated. Using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, we found that FDV has the highest activity of the antioxidants. After spreading FDV onto tryptic soy broth and yeast extract-peptone-dextrose agar media, the microbial strains were isolated and characterized through physiological and biochemical analysis. Based on 16S ribosomal DNA sequence analysis, the isolated microorganisms exhibited a close similarity to Acetobacter papayae, Acetobacter pasteurianus, and Acetobacter peroxidans.

• Journal of radiological science and technology
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• v.11 no.1
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• pp.71-77
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• 1988

To improve the storage method for kimchi, optimal ripening kimchi was irradiated with doses of 1, 3, 5kGy Co-60gamma radiation, followed by the microbiological, physicochemical and senosory evaluations during storage at $5^{\circ}C$. 1. Total aerobic count increased in the beginning of storage and then decreased slowly as the number of total lactobacilli (anaerobe) increased. The above, total aerobic and lactobacilli were reduced by 1 to 3 log cycles with irradiation and at the 90th day after storage the number of total lactobacilli remained $1.30{\times}10^{8}$ per ml in 3 kGy irradiated group. Irradiation treatment at 3 kGy sterilized coliforms and molds contaminating the sample as the level of $2.0{\times}10^{4}$ per ml and $5.4{\times}10^{2}$ per ml respectively and no apparent growth was observed in both control and 1 kGy irradiated groups after 20 days of storage. The population of yeast, $3.5{\times}10^{3}$ per ml initially, increased steadily during kimchi storage and at 90 days of storage the number was shown to be $5.6{\times}10^{4}$ per ml and $6.5{\times}10^{2}$ per ml in control and 3 kGy irradiated groups, respectively. 2. In the physicochemical changes during kimchi storage, pH, acidity and volatile acid of non-irradiated control at the 45th day after storage were 4.0, 0.7% and 0.066%, while those of 3 kGy irradiated group were 4.2, 0.59 and 0.06% at the 90th day of storage, respectively. The reducing sugar content of all stored samples changed inversely total acidity content, indicating irradiation delayed the changes of them. The amount of ascorbic acid decreased gradually with the storage time and irradiation dose increase. Textural parameters of 3 kGy irradiated group were superior to those of other groups at the latter stage of storage. 3. Sensory evaluations showed that 3 kGy irradiation was the optimum dose level to extend the shelf-life of kimchi more than two months as compared to control.

• Journal of Nutrition and Health
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• v.16 no.4
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• pp.296-302
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• 1983

The estimation of the nutritional requirements at the national or population level has a great difficulty in calculating the cumulative effects of the several variables, i. e. age, sex, weight activity, etc., in order to adapt nutrient requirements to the condition of a country or to a population group. The Joint FAO/WHO Expert Group on nutrient requirements had proposed a simpler model, an average daily per capita nutritional requirements that will enable the different parameters to incorporated in a single calculation table. The average daily per caita nutritional requirements for Korean-1982 calculated by this proposed method are as follows : energy, 2,200 kcal ; protein, 70g : calcium, 0.72g ; iron, 14mg; vitamin A, 1,900 IU ; ascorbic acid, 50mg ; thiamin, 0.9mg ; riboflavin, 1.2mg ; niacin equivalent, 15mg. The average daily per capita nutritional requirements would be used to assess the adequacy of the national dietary intakes and provide basic information for the establishment of national food production and consumption policies and the planning of programmes aiming at an adequate and equitable distribution of food supplies. On a different levels, they would be used widely in the planning of diets for a specific population group, and also provide important reference information for the epidemiology study of nutritional deficiencies.

• Journal of Nutrition and Health
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• v.29 no.6
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• pp.622-633
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• 1996

The purpose of present study was to assess the change of bone mineral density (BMD) by age and the dietary factors influcencing on BMD in Korean women in Taegu. The subjects were 242 healthy female in the range of 7-67 years old, and were divided into 4 age groups. BMD of lumbar of lumbar spine, femur(neck, ward's triangle, trochanter)and total body was measured by dual energy X-ray absorptionmetry. The nutrient intake measured by convenient method was similar to or more than the level of RDA. The significant relationship between nutrient intake and BMD was observed. Particularly for lumbar spine and total body in group 4 (50-60yr), such as energy, carbohyrate, protein, fat, Ca, animal Ca, meat Ca, Fe, thiamin and niacin were found significantly positive correlations. By analysis of multiple regression, significant relationships were shown between protein and lumbar spine and total body BMD in group 4, between ascorbic acid and total body BMD in group 2(17-34 yr). Energy expenditure showed better corrlations with BMD rather than nutrient intake. BMD was significantly greater in subjects consuming a mean dietary Ca intake more than 125% of RDA compared with less than 75% of RDA. In high Ca intake group ($\geq$125% of RDA), there were the significantly negative correlations between animal (meat) Ca and BMD in each bone of 7-9 years. The excessive intake of animal protein in this age group was found. And the correlations between BMD and past milk consumptin were significant in all skeletal sites of group 1(7-16 yr). This study confirms that the most effective way of preventing osteoporosis and the fractures is to maximize peak bone mass in early life and to minimize bone loss through the balanced adequate intake of Ca and other nutrients and regular physical activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.133-137
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• 2001

The antioxidant activitiesof methanol extracts of twenty one vegetables were tested using the method of 1,1-diphenyl-2-picryl hydrazyl (DPPH) reactivity and TBARS substance assay in vitro. The methanol extracts of the leaves from three plants such as Aster scaber, Chrysanthemum coronarium, Petasites japonicus were found to be th most effective on DPPH radical scavenging activity. The next effective ones were the leaves of Capsicum annuum, the peels of Ipomoea batatas and Solanum tuberosum, the stems and leaves of Ipomoea batatas, the levels of Solanum melongena, the fruits of Solanum melongena, the green fruits (seed) of Capsicum ammuum in order, and the others did not show a considerable activity. When tested on lipid peroxidation using a lipid peroxidation generation system mediated by $H_{2}O_{2}/Fe^{2+}$ in rat liver homogenates. the peels of Cucumis melo, the leaves and the fruits of Solanum melongena, of Solanum melongena, The levels of Aster scaber and Chrysanthemum coronarium, the stems and leaves of Ipomoea batatas and the peels of Ipomoea batatas were found to exhibit a good protective activity against lipid peroxidatian in the order of effectiveness.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2012.05a
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• pp.18-18
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• 2012

Antioxidant is an important role to protect the human body against damage by reactive oxygen species. However, the excessive intake of such antioxidant is known to cause a serious poisonous influence on one's liver, lungs and circulating system. Therefore, it is necessary to develop a safe natural antioxidant. For the purpose of developing natural antioxidant and antibacterial, the antioxidant activity and antibacterial effects of various extract solvents from Artichoke (Cynara Scolymus L.) leaf were determined. In this study, the extracts of Artichoke leaf dried from solvent extraction were examined by means of DPPH free radical scavenging activity and ABTS free radical scavenging activity. The effect of free radical scavenging compared with $\alpha$-tocopherol and L-ascorbic acid. In Artichoke leaf extract, evaluated by using DPPH and ABTS showed that the highest antioxidant activities were found to be in methanol extracts from DPPH radical ($IC_{50}$: $20.06{\mu}g\;mL^{-1}$), ABTS radical ($IC_{50}$: $16.01{\mu}g\;mL^{-1}$) and followed by ethanol > methyl chloride > ethyl acetate > n-Hexane. By using disc diffusion method, the antibacterial activity showed that the Artichoke leaf extract was found to be most effective against all of the tested organisms and the methyl chloride extract showed the most significant antibacterial effect against all of tests among 5 solvents extract, followed by ethyl acetate > n-Hexane > ethanol > methanol. As a result, optimal in antioxidant activity for Artichoke (Cynara Scolymus L.) leaf is methanol extract and for antibacterial effect is Methyl Chloride extract.

• Journal of Nutrition and Health
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• v.12 no.3
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• pp.41-46
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• 1979

Almost all Korean women in rural area breast feed their children for average 18 to 24 months. Since they breastfeed their children for long period the need for the lactating mot­hers to be nutritionally refurnished becomes evidently great. However the studies on the nutrient intake level of these mothers has been very scarce. We have studied the food and nutrient intake level of 93 lactating women randomly selected from rural areas of South Korea. Thirty one well trained and experienced surveyors conducted the dietary survey by the. combination method of precise weighing and interview for two 'consecutive days. Briefly stating the findings 1) The dietary pattern of the lactating women in rural Korea was not different from the ordinary Korean diet-i.e no conscientious effort to improve the quality of the diet was apparent. 2) Consequently over 90% of the total food intake was made up with the typical rice­kimchi diet. 3) The quantity of the total food intake was greater than the national average sufficient intake of calorie was observed. 4) No milk or the milk products were consumed by the lactating women in rural Korea. 5) Average intake of protein was 88 grams. Only 5% of these was provided by the animal foods. 6) Mean daily intakes of niacin, thiamin and ascorbic acid exceeded the recommended allowances. But vitamin A intake was 1171 IU-about 33% of the RDA-and the riboflavin intake was 0.92 mg. which is about 54% of the recommended level for the lactators. 7) Average calcium intake was 490 mg.-41% of the RDA. The iron intake was adequate.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1195-1198
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• 2013

Nickel hexacyanoferrate supported palladium nanoparticles (Pd-NiHCF NPs) were synthesized and studied for oxygen reduction reactions in direct methanol fuel cell. The NiHCF support was readily synthesized by a comixing of $Ni(OCOCH_3)_2$ and equimolar $K_3[Fe(CN)_6]$ solution into DI water under rigorous stirring. After the preparation of NiHCF support, Pd NPs were loaded on NiHCF via L-ascorbic acid reduction method at $80^{\circ}C$. Pd-NiHCF NPs were electrochemically active for oxygen reduction reaction in 0.1 M $HClO_4$ solution. X-ray absorption near edge structure analysis was conducted to measure the white line intensity of Pd-NiHCF to verify the OH adsorption. As a comparison, carbon supported Pd NPs exhibited same white line intensity. This study provides a general synthetic approach to easily load Pd NPs on porous coordination polymers such as NiHCF and can provide further light to load Pd based alloy NPs on NiHCF framework.