• Journal of Food Hygiene and Safety
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• v.29 no.1
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• pp.21-25
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• 2014

Formaldehyde and phenol used in the production of melamine-wares may be intended to come into foodstuffs. So this study investigated the migration of formaldehyde and phenol from 222 articles Articles were cups(14), bowls(75), plates(85), spoons(10), chopsticks(4), food trays(8), rice paddles(4), spatulas(9) and scoops(12). The food stimulants were 4% acetic acid, 20% ethanol, distilled water and n-heptane. Korea regulation (Standards and specifications for food utensils, containers and package) specifies migration limits for formaldehyde and phenol in food stimulants. Formaldehyde and phenol are restricted by 4 mg/L, 5 mg/L respectively. In all cases the migration of formaldehyde and phenol were below the limit set in Korea regulation. The level of formaldehyde and phenol migrated to food simulants were in the range of N.D~2.949 mg/L, N.D~0.078 mg/L respectively. These migration results of formaldehyde and phenol will provide a scientific basis for the safety management of melamine-wares.

• Korean journal of food and cookery science
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• v.21 no.2 s.86
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• pp.263-269
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• 2005

Citrus juice, a concentrate manufactured by the Jeju Provincial Corporation, was converted into vinegar orderly by alcohol and acetate fermentation. The juice with 6 folds dilution by distilled water was used as the sole nutrient source through out experiments. Diluted juice contained $12.96^{\circ}Brix$ of total sugar, $0.632\%$ of total acid and $20.23{\mu}g/m{\ell}$ of hesperidin. Naringin was not detected from the juice. Citrus wine having $5.6\~6.3\%$ alcohol was produced from diluted juice by 3 days of fermentation at $28^{\circ}C$. A kind of malomelo yeast CMY-28 was used for wine fermentation. The wine was succeedingly fermented for 8 days at $30^{\circ}C$ after inoculation of seed vinegar which contained active cells of acid producing bacteria CV1. Inoculum size of seed vinegar was controlled to $10\%$(v/v) of citrus wine. The wine converted into vinegar by the fermentation. Citrus vinegar, the final product of fermentation, was colored with very thin radish-yellow and transparent. It's acidity ranged between $5.8\~6.2\%$ as acetic acid. The vinegar got the best score by sensory test among several natural fruit vinegars. It was clear from the results that citrus vinegar in high quality could be produced from concentrated citrus juice, however fermentation conditions should be improved to reduce the amount of reducing alcohol.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.35-41
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• 2006

Possible application of hurdle technology extention of shelf-life of fresh-cut apples was investigated by evaluating various hurdle factors known to be effective microbial growth inhibitors and their synergistic effects. Fresh-cut apples treated with chitooligosaccharide or grapefruit seed extract (GSE) showed higher microbial counts than those treated with distilled water during latter half of storage period, and at high concentrations. Citric and malic acids showed similar results, although microbial counts of fresh-cut apples treated with 0.75% or higher concentration of citric acid increased at 4 days of storage at $18^{\circ}C$, indicating malic acid is more effective than all hurdles tested for controlling microbial growth. Using ascorbic acid and calcium chloride as additional hurdles to control browning and softening, minimum and maximum compositions of dipping solution were: 0.25 : 0.5 : 0.25% and 0.75 : 1.0 : 0.75% malic acid: ascorbic acid: calcium chloride, respectively.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.998-1001
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• 2002

Micro-LC method for the quantitative determination of hydrogen peroxide in foods has been established. This method was carried out on cation-exchange resin gel column using distilled water as mobile phase with 50 mM sodium sulfate as electrolyte. The detection was performed with an electrochemical detector (ECD) at 0.6 voltage. Under this analytical condition, the recovery rates of hydrogen peroxide in tomato and lemon were 98.3 and 97.4%, respectively. Among 28 food types, hydrogen peroxide concentrations were 0.6, 0.5, 1.9, 0.9, 0.5, 0.6, 0.9, 0.8, and 0.4 ppm in banana, peach, orange, strawberry, pepper, onion, cucumber, burdock, and egg plant, respectively, Whereas none was detected in remaing 19 samples.

• Restorative Dentistry and Endodontics
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• v.30 no.1
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• pp.22-30
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• 2005

The purpose of this study was to compare the effect of surface sealing materials on microleakage and surface roughness in Class V composite restorations. Twenty five standardized Class V cavity preparations were made on the facial surface of human premolars and were randomly assigned to 5 groups. The teeth were restored with Z-250 after applying Single Bond. Following 7 days storage in distilled water at $37^{\circ}C$, the restorations were sealed as following systems : No sealing ; Single Bond Adhesive ; Biscover ; Fortify ; Optiguard. Then, toothbrush abrasion test was conducted using a wear testing machine. Surface roughness was measured by means of profilometer before and after toothbrushing and the results were statistically analysed by using a paired t-test and ANOVA. The bonded interfaces and the changes of surface roughness were examined by SEM. For microleakage test, specimens were stained in a $2\%$ methylene blue solution, then longitudinally sectioned and analyzed for leakage at occlusal and cervical interfaces using stereomicroscope. The results were statistically analysed by using a Kruskal-Wallis and Mann-Whitney U test. Surface roughness was increasing in all groups after toothbrushing, but no statistically significant differences. In SEM observation, surface sealant was partially retained and partially detached in bonded interfaces. Especially, microgap was identified in cervical margins. In microleakage test, there was better seal in the enamel region and a significant difference between groups at occlusal margin. Control group and Single Bond group had significantly better marginal seal at enamel margin than cervical margin.

• Restorative Dentistry and Endodontics
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• v.29 no.6
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• pp.548-552
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• 2004

Intracanal disinfection of infected root canal is one of important treatment procedure. This in vitro study aimed to evaluate whether the surface polymers of controlled release drug (CRD) can effectively control the release rate of chlorhexidine for root canal disinfection. Four CRD prototypes were prepared: Group A (n=12); The core device (absorbent paper point) was loaded with 40% CHX solution as control. Group B (n=12); same as group A, but the device was coated with chitosan. Group C (n=12); same as group A and then coated three times with 5% PMMA. Group D (n=12); same as group A and then coated three times with 3% PLGA. All CRD prototypes were soaked in 3 mL distilled water for experimental periods and the concentrations of released CHX from each CRD prototype were determined using a UV spectrophotometer. Results showed that release rate of CHX were the greatest in the non-coated group (control group), followed by the chitosan-coated group, the PLGA-coated group, and the PMMA-coated group (P < 0.05). This data indicate that surface polymers can control the release rate of CHX from the CRD prototypes.

• Restorative Dentistry and Endodontics
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• v.35 no.6
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• pp.486-491
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• 2010

Objectives: This study examined the effect of 2% chlorhexidine on the ${\mu}TBS$ of a direct composite restoration using one-step self-etch adhesives on human dentin. Materials and Methods: Twenty-four extracted permanent molars were used. The teeth were assigned randomly to six groups (n = 10), according to the adhesive system and application of chlorhexidine. With or without the application of chlorhexidine, each adhesive system was applied to the dentin surface. After the bonding procedure, light-cure composite resin buildups were produced. The restored teeth were stored in distilled water at room temperature for 24 hours, and then cut and glued to the jig of the microtensile testing machine. A tensile load was applied until the specimen failed. The failure mode was examined using an operating microscope. The data was analyzed statistically using one-way ANOVA, Student's t-test (p < 0.05) and Scheffet's test. Results: Regardless of the application of chlorhexidine, the Clearfil $S^3$ Bond showed the highest ${\mu}TBS$, followed by G-Bond and Xeno V. Adhesive failure was the main failure mode of the dentin bonding agents tested with some samples showing cohesive failure. Conclusions: The application of 2% chlorhexidine did not affect the ${\mu}TBS$ of the resin composite to the dentin using a one-step self-etch adhesive.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.915-923
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• 2017

The by-products of red ginseng marc showing the improvement of health has been strongly studied because of the expectation of possibility to be used as the functional foods. This research was to investigate the extraction, separation, isolation, and evaluation of crude acidic polysaccharides related to antioxidant activity, sequently chemical structure of those products was evaluated by FT-IR and NMR. Compared with other solvents such as ethanol, methanol, propanol, acetone, and butanol, ethanol was selected. The concentration of red ginseng solution for extraction was selected as 10%(w/v) related to extraction yield(11.95%) and amount(11.8 mg/ml). In the ion exchange chromatography, aidic polysaccharides showing the highest antioxidant activity was obtained when eluted by distilled water. As results of structural analysis by FT-IR and NMR, peaks corresponding to C-O, C-O-O-, C-H, anomeric C-6, and repeated C-1 and C-6 linkages was to be presumed to be ($1{\rightarrow}6$) glycosidic linkage with the typical acidic polysaccharide.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.587-593
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• 1998

To elucidate anti-tumor promoter from seaweed, the anti-tumor promoting activity of Ecklonia stolonifera, Undaria pinnatifida and Laminaria japonica extracts were determined by Epstein-Barr virus (EBV)-early antigen (EA) induction caused by a tumor promoter, teleocidin B-4. The methanol extracts of seaweed were subsequently fractionated with diethyl ether, distilled water, chloroform and ethyl acetate. Among the solvent fractions tested, chloroform and ethyl acetate fraction of E. stolonifera showed a high anti-tumor promoting activity at the levels of 88.0 and $85.9\%$ by the addition of 20 ${\mu}g/m{\ell}$, respectively. To characterize anti-tumor promoters from solvent fractions of E. stolonifera, the effects of phenols, chlorophyll derivatives and carotenoids on the anti-tumor promoting activity were investigated. Phenols, such as bromophenol and phloroglucinol showed anti-tumor promoting activity of $57\~66\%$ at 20 ${\mu}g/m{\ell}$. Pigments, such as chlorophylls and carotenoids exerted high anti-tumor promoting activities. Chlorophyll a and pheophorbide a exhibited the activity of $77.4\%$ and $66.6\%$ at 5${\mu}M/m{\ell}$, respectively. The active compounds of carotenoids were tentatively identified as lutein and $\alpha-cryptoxanthin$ from the profiles of visible spectra and R_f value of their authentic compounds, and showed anti-tumor promoting activities of $76.9\%$ and $84.4\%$ at dose of 20 ${\mu}g/m{\ell}$, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.3
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• pp.313-320
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• 2016

In the present study, we examined whether or not an herbal mixture extract (HME) has attenuation effects on immobilization stress and sleep disturbance in rats. Immobilization stress was induced by restricting movement using a constraint box for 2 h, and sleep disturbance was induced by exposure to 300 lx of constant light for 24 h and injection of caffeine (1 mg/kg, i.p.). Rats were orally treated with distilled water (vehicle) or HME for 3 weeks at different doses of 10, 30, and 100 mg/kg/d (HME I, II, and III, respectively). In the immobilization model, HME III treatment significantly decreased adrenal gland weight, whereas HME II and III treatment reduced plasma levels of cortisol. HME II and III also reduced the level of IL-6. In the sleep disturbance model, HME II and III meaningfully reduced the plasma level of cortisol, and the increased plasma level of melatonin. HME III significantly increased body weight. HME reduced immobilization stress and ameliorated disturbance in rats. These findings suggest that HME may have beneficial potential for attenuation of sleep disturbance and stress.