• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.504-510
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• 1988

The physicochemical properties of rice flours which were obtained by dry milling(blade, hammer, test and micro mill) and wet & dry milling (roller & micro mill) were investigated. The resulting flour particle sizes were reduced in the order that of blade, hammer, test, micro and roller & micro mill. Scanning electron microscopic examination showed that the starch granules were freed from the imbedding matrix as the particles became finer. The test-milled flour had the hightest levels of starch damage, maltose value and hot-water soluble amylose content, and the blade-milled flour showed the lowest levels. Amylograph viscosity and gelatinization temperature of the flours decreased as the particles became finer, and the addition of $Hg^{+2}$ increased the peak viscosity of the dry-milled flour pastes, whereas the wet & dry-milled flour did not show any changes. The blue values and ${\lambda}$max values of the iodine complex of the cold-water extractable ${\alpha}-D-glucan$ from flours were in the range of 0.023-0.029 and 518-522nm, respectively, indicating these materials were shown to be mainly composed of amylopectin-like polymer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.10
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• pp.1235-1240
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• 2007

For this study, plant material for development of phytobiotics (feed additives made with plant extract) was screened. Among hot-water extracts of 9 medicinal plants, Fallopia japonin showed the highest antioxidative activity; the electron donating ability (EDA) and nitrite scavenging ability were 86.9% and 92.7%, respectively. Also, F. japonica had the antimicrobial activity for Pseudomonas aeruginora, Escherichia coli, Bacillus cereus, Salmonella Typhimurium, Listeria monocytogenes, Klebsiella pneumoniae, Staphyzococcus aureus. Specially, antimicrobial activity of F. japonica against K. pneumoniae, and S. aureus was vet strong. $IC_{50}$ of F. japonica against K. pneumoniae, and S. aureus was 6.24 mg/mL and 1.8 mg/mL respectively. These results suggested that F. japonica was a candidate for a phytobiotic material.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.435-441
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• 2012

The direct conversion of cellulose into polyols in $H_2$ was examined over Pt catalysts supported on various zeolites, viz., mordenite, Y, ferrierite, and ${\beta}$. For comparison, Pt catalysts supported on ${\gamma}-Al_2O_3$, $SiO_2-Al_2O_3$, and $SiO_2$ were also tested. The physical properties of the catalysts were probed with $N_2$ physisorption. The surface acidity was measured with temperature programmed desorption of ammonia ($NH_3$-TPD). The Pt content was quantified with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The Pt dispersion was determined with CO chemisorptions and transmission electron microscopy (TEM). The conversion of cellulose appeared to be mainly dependent on the reaction temperature and reaction time because it depends on the concentration of $H^+$ ions reversibly formed in hot water. Pt/H-mordenite (20) showed the highest yield to polyols among the tested catalysts. Pt/H-zeolite was superior to Pt/Na-zeolite for this reaction. The polyol yield was dependent on the surface acid density and the external surface area.

• Korean Journal of Materials Research
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• v.2 no.5
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• pp.330-336
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• 1992

Four distinctive hot pressed and heat treated S${i_3}{N_4}$ceramics, S${i_3}{N_4}$-8%${Y_2}{O_3}$, S${i_3}{N_4}$-6% ${Y_2}{O_3}$-2% $A{l_2}{O_3}$, S${i_3}{N_4}$-4% ${Y_2}{O_3}$-3% $A{l_2}{O_3}$, 그리고 S${i_3}{N_4}$-1% MgO-1% Si$O_2$(in wt%), were prepared and characterized by X-ray diffraction, scanning electron microscopy, image analysis and mechanical tests. The fracture toughness of S${i_3}{N_4}$-8% ${Y_2}{O_3}$specimens containing large elongated grains showed the highest value of about 9.8MPa$m^{1/2}$. Two out of four S${i_3}{N_4}$, ceramics(S${i_3}{N_4}$-6% ${Y_2}{O_3}$-2% $A{l_2}{O_3}$and S${i_3}{N_4}$-4% ${Y_2}{O_3}$-3% $A{l_2}{O_3}$) heat treated at 200 $0^{\circ}C$retained the fracture strength of over 900MPa and fracture toughness of over 8.0MPa$m^{1/2}$. Large ${\beta}$-S${i_3}{N_4}$grains having a diameter larger than 1${\mu}$m appeared to contribute to increase in fracture toughness.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.632-638
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• 1997

To develop the Instant Nuroong-gi in a short reconstitution time, we made puffed Instant Nuroong-gi samples and investigated their physicochemical characteristics. The Nuroong-gi was prepared using a Japonica variety with three different cooking conditions: steam cooker(process A), pressure cooker (process B) and cabinet cooker(process C). The Instant Nuroong-gi is produced by adding water to the Nuroong-gi which is broken into the size of 0.5~1.0cm. The amount of the added water is 40% of the weight of the broken Nuroong-gi. And it was puffed at 160~17$0^{\circ}C$ for 30 secands. The water binding capacity of Instant Nuroong-gi samples was 7.2 at process A, 6.5 at process B and 6.6 at process C. The total sugar content of Instant Nuroong-gi samples in hot water reached at the highest level at 3-minute cooking time. Through the sensory evaluation by a panelists, we discovered that Instant Nuroong-gi prepared by a steam cooker showed the highest roasted nutty taste, hardness, stickiness and overall acceptability. And Instant Nuroong-gi prepared by a pressure cooker showed the highest color, clearness, and roasted nutty flavor. Correlation coefficients between overall acceptability and other sensory attributes of Instant Nuroong-gi indicated that hardness had the most significant correlation to sensory evaluations. When we compared the results of color test with those of sensory evaluation of Instant Nuroong-gi prepared by three different cookers, we discovered that panelists preferred yellow Instant Nuroong-gi prepared by a pressure cooker. We found some morphological properties of Instant Nuroong-gi as a result of the comparison of the crystalization by a X-ray diffraction analysis and the observation of the shapes by a the scanning electron micrographs.

• Applied Chemistry for Engineering
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• v.32 no.2
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• pp.143-148
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• 2021

A thermally conductive 200 ㎛ thick polyimide-based film was made from a polyamic acid (PAA) precursor containing graphene prepared from graphite rod using an electrostatic discharge method in order to improve the thermal conductivity and expand the applicability of polyimide (PI) film. Properties of graphene produced by electrostatic discharge were measured by Raman spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). As a result of Raman spectrum and XPS analyses of as-prepared graphene, the ID/IG ratio was 0.138 and C/O value was 24.91 which are excellent structural and surface chemical properties. Moreover, thermal conductivities of polyimide films increased exponentially according to graphene contents but when the graphene content exceeded 40%, the polyimide film could not maintain its shape. The thermal conductivity of carbonized PI film made from PAA containing 40 wt% of graphene was 51 W/mK which is greatly enhanced from the pristine carbonized PI film (1.9 W/mK). This result could be originated from superior properties of graphene prepared from the electrostatic discharge method.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1087-1096
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• 2010

This study was conducted to investigate the physiological activity of extracts of fresh mushrooms. The components were extracted by hot water; subsequently, the hot-water extract was subjected to 60% ethanol precipitation to yield high-molecular-weight (HMW) and low-molecular-weight (LMW) fractions. Total polyphenol contents, $\beta$-glucan contents, electron-donating ability (EDA), superoxide dismutase (SOD)-like activity, nitrite-scavenging activity, fibrinolytic activity, nitric oxide (NO) production, and inhibition of NO production of the mushroom extracts were measured using lipopolysaccharide (LPS)-stimulated murine macrophages, RAW 264.7 cells. The extracts of Lentinus edodes (Berk.) Singer and Pleurotus ostreatus (Fr.) Kummer contained the highest levels of $\beta$-glucan (33.5% and 25.57%, respectively). Further, the LMW fractions of the Phellinus linteus contained the highest levels of polyphenols (233.23 mg/g). The EDA of LMW fractions (10 mg/mL) of the Phellinus linteus and Agaricus bisporus were 80.74% and 51.35%, respectively. Further, SOD-like activities of the LMW fractions were high as compared to those of the HMW fractions. Nitrite-scavenging activities of the LMW fractions (pH 1.2; concentration, 10 mg/mL) of the Phellinus linteus and Pleurotus ostreatus (Fr.) Kummer were 75.95% and 41.05%, respectively. The fibrinolytic activity of the LMW fractions of all mushrooms showed no enzyme activity by fibrin plate assay. The fibrinolytic activity of the extracts of Tricholoma matsutake was the greatest inhibitory activity at 60.4%. Further study revealed that the mushroom extracts exhibited anti-inflammatory effects on RAW 264.7 cells. The LMW fraction ($500\;{\mu}g/mL$) of the Phellinus linteus considerably inhibited NO production (100%).

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.6
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• pp.684-690
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• 2008

To investigate the applicability of hot water extract (PLW) and ethanol extract (PLE) from Phellinus linteus as functional food and cosmeceutical materials, its total flavonoids content, total phenolics content, electron donating ability (EDA), nitrite-scavenging ability (NSA), SOD-like activity, inhibitory effect of tyrosinase and elastase were examined. Total flavonoids contents of PLW and PLE were 17.31 mg/g and 42.61 mg/g, respectively, and total phenolics contents were estimated as 149.92 mg/g for PLW and 432.42 mg/g for PLE. The EDA of PLW and PLE were $6.49{\sim}92.98%$ and $22.61{\sim}94.28%$. The EDA and total phenolics contents had a high correlation of 0.83. The NSA was pH dependent, and was highest at pH 1.2 and lowest at pH 6.0. The NSA of PLE was higher than that of PLW. The SOD-like activities of PLW and PLE were $14.36{\sim}35.21%$ and $17.27{\sim}81.84%$, respectively, and the activity was dependent on the sample concentration. The tyrosinase inhibitory activity was the highest in PLE ($10.51{\sim}80.93%$) while that of PLW was $4.77{\sim}43.69%$. Finally, the elastase inhibitory activity was $10.01{\sim}76.02%$ at PLE. Based on the above results, we deemed that the ethanol extract of Phellinus linteus was the most pertinent for use as functional food and cosmeceutical materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.581-591
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• 2017

The purpose of this study was to examine the biological activities of gamma-irradiated Teucrium veronicoides. In photostimulated luminescence analysis, non-irradiated sample showed lower than 700 photon counts (PCs), whereas irradiated (5 and 10 kGy) samples showed higher than 700 PCs. The thermoluminescence ratio of non-irradiated samples was less than 0.1, whereas the values of irradiated samples were greater than 0.1. Electron spin resonance analysis was performed confirmed for irradiation identification. The total phenolic contents of hot-water and 50% ethanol extracts were higher than those values after irradiation at 10 kGy. Regarding 1,1-diphenyl-2-picrylhydrazyl radical inhibitory activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity, antioxidant protection factor, thiobarbituric acid reactive substance inhibitory activity as antioxidant test and xanthine oxidase inhibitory activity, the effect of gamma irradiation had on significant effects. On the other hand, ${\alpha}-amylase$ inhibitory activity of 10 kGy-irradiated hot-water extract was 23.6% higher than that of the non-irradiated sample. Thus, gamma irradiation could be used for the long-term storage of Teucrium veronicoides.

• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.254-265
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• 2021

As a result of measuring the polyphenol content of Humulus japonicus (HJ) extract according to the collection time and extraction solvent, bothhot water extract and 70% ethanol extract were collected and extracted in June, and the polyphenol content was high. When the harvesting time was the same, the polyphenol content of the ethanol extract was higher than that of the hot water extract. As a result of measuring the antioxidant activity of HJ extract by measuring electron-donating ability, SOD-like activity, and ABTS radical scavenging ability, HJ6E, which has the highest polyphenol content, showed the highest activity. In addition, in the case of the extract collected in August, the polyphenol content was similar. However, the antioxidant activity of the ethanol extract was high, sothe antioxidant activity remained high when extracted with 70% ethanol. As a result of measuring tyrosinase inhibitory activity for evaluating skin whitening activity, HJ6W did not show any activity. The activity at the highest concentration was 16.18% for HJ8W, 8.07% for HJ6E, and 14.7% for HJ8E. Therefore, the content of ingredients showing skin whitening activity was higher in August than in June. In the elastase inhibitory activity for evaluating the anti-wrinkle activityof the skin, the ethanol extract showed very little activity, and the hot water extract did not. In addition, since all extracts do not show astringent activity, it is judged that it is not appropriate to use HJ as a functional ingredient for preventing wrinkle formation. As a result of measuring the cell viability of HJ6E, which showed the highest polyphenol content and antioxidant activity, it showed a cell proliferation effect at low concentrationsbut strong cytotoxicity at concentrations above 50 ㎍/mL. In the case of the NO production inhibitory ability, as the concentration increased, the NO production of Raw 264.7 was suppressed. Theamount of NO production at 1,000 ㎍/mL decreased to 40.7%. However, whether these results are due to cytotoxicity or the extract's efficacy is a part that requires further research.