• Food Science of Animal Resources
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• v.32 no.5
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• pp.652-658
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• 2012

This study was carried out to identify the ACE (Angiotensin converting enzyme) inhibitory activity of casein hydrolysates for development of anti-hypertensive hydrolysates. Sodium caseinate was treated with six kinds of commercial proteases such as Flavourzyme, Protamex, Neutrase 1.5, Alcalase, Protease M, and Protease S for 8 h individually, and was then treated with the enzyme combination for 4 h at $45^{\circ}C$. The hydrolysate which had the highest ACE inhibitory effect was then hydrolysed successively with three digestive enzymes: pepsin, trypsin, and ${\alpha}$-chymotrypsin, at $37^{\circ}C$ for 4 h under conditions mimicking those of the gastrointestinal tract. UF (ultra filtration) treatment was applied to one of the secondary hydrolysates to determine ACE inhibitory activity. When sodium caseinate was hydrolysed by commercial proteases, the degree of hydrolysis (DH) showed 2.54 to 4.25% and after secondary hydrolysis, DH showed 4.30 to 5.22%. ACE inhibitory activity and $IC_{50}$ values decreased, and inhibition rates increased during hydrolysis. Protamex treatment showed the lowest $IC_{50}$ value ($516{\mu}g/mL$) and Flavourzyme hydrolysate showed the highest $IC_{50}$value ($866{\mu}g/mL$). As the first hydrolysate was treated with Flavourzyme, the ACE inhibitory activity increased. Neutrase hydrolysate had the highest activity with an $IC_{50}$ value ($282{\mu}g/mL$). When Neutrase plus Flavourzyme treatment was hydrolyzed by digestive enzymes, the $IC_{50}$ value ($597{\mu}g/mL$) was decreased statistically (p<0.05). As Neutrase plus Flavourzyme hydrolysate is treated by UF with MW cut-off 10,000, permeate showed $273{\mu}g/mL$ of $IC_{50}$ value, showed no difference, but retentate which has over MW 10,000 showed statistically different $IC_{50}$ value, $635{\mu}g/mL$ (p<0.05).

• Food Science of Animal Resources
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• v.27 no.1
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• pp.53-59
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• 2007

This study was conducted to determine the effects of dietary supplementation with probiotics on the growth and meat quality of finishing pigs. A total of forty eight ($Landrace{\times}Yorkshire{\times}Duroc$) pigs ($55.3{\pm}1.5 kg$ average initial body weight) were randomly assigned to four groups and fed on a diet supplemented with 0, 0.2, 0.5 or 1% probiotics for 58 days. The pigs were slaughtered at approximately 105 kg live weight. Supplementation with 0.2% probiotics significantly (p<0.05) increased daily gain compared to the control. The daily gain of pigs in the 0.2% probiotic group was 0.95 kg whereas that of the control was 0.85 kg. The average feed intake was 2.79-2.84 kg and there were no significant differences in feed intake between the control and test groups. The feed conversion of the 0.2% probiotic group was 2.96 kg whereas the control showed a feed conversion of 3.28 kg. The results of this study imply that supplementation with 0.2% probiotics may improve the feed conversion of pigs. There were significant differences in carcass weight, carcass ratio, backfat thickness, and frequency percentage of A grade carcasses between the control and probiotic test groups. In addition, the moisture, crude protein and crude ash contents of the probiotic treated groups did not differ significantly from the control group, however the crude fat values of the 0.2% probiotic test group was significantly tower than the other groups. The muscle pH levels of all samples ranged from 5.63-5.67 which is the normal pH of pork. The supplementation of probiotics resulted in decreased lightness ($L^*$) values and increased redness ($a^*$) values. Furthermore, the saturated fatty acid contents of the 0.2% and 0.5% probiotic test groups decreased and the unsaturated fatty acid contents increased relative to the control.

• Food Science of Animal Resources
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• v.27 no.1
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• pp.117-121
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• 2007

The number of internet users and the scale of electronic on-line trading are on the increase due to the development of information technology and the internet. The aim of this study was to monitor the accuracy of country-of-origin labels and the indicated contents of meat available by electronic on-line trading by using a structural interview sheet for 100 on-line meat product markets. The result of this investigation showed a 100% level of accuracy for business name and telephone number whereas the company address, meat manufacturer and supplier, and business registration were less reliable. We also investigated the accuracy of site policy, e-mail address, and fax number. The results showed that the accuracy of fax numbers was the lowest. The product name and the kind of meat actually in the product showed a 100% level of conformity, while the price (96.3%), place of origin (93.6%), capacity (90.4%), meat parts (80.9%) and contents of the product (73.4%) showed a relatively low level of conformity. Serious safety issues were exposed by the disturbingly low 20.2% accuracy of indicated expiration dates and 5.3% accuracy of indicated manufacturing dates. To ensure food safety, it is essential to improve consumer understanding and trust regarding food safety through continuous public relations. More education and information are needed to raise consumer awareness of the facts versus myths regarding food safety.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.343-356
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• 2016

The Korea Radioactive Waste Agency (KORAD) has developed a dual-purpose metal cask for the dry storage of spent nuclear fuel that has been generated by domestic light-water reactors. The metal cask was designed in compliance with international and domestic technology standards, and safety was the most important consideration in developing the design. It was designed to maintain its integrity for 50 years in terms of major safety factors. The metal cask ensures the minimization of waste generated by maintenance activities during the storage period as well as the safe management of the waste. An activation evaluation of the main body, which includes internal and external components of metal casks whose design lifetime has expired, provides quantitative data on their radioactive inventory. The radioactive inventory of the main body and the components of the metal cask were calculated by applying the MCNP5 ORIGEN-2 evaluation system and by considering each component's chemical composition, neutron flux distribution, and reaction rate, as well as the duration of neutron irradiation during the storage period. The evaluation results revealed that 10 years after the end of the cask's design life, $^{60}Co$ had greater radioactivity than other nuclides among the metal materials. In the case of the neutron shield, nuclides that emit high-energy gamma rays such as $^{28}Al$ and $^{24}Na$ had greater radioactivity immediately after the design lifetime. However, their radioactivity level became negligible after six months due to their short half-life. The surface exposure dose rates of the canister and the main body of the metal cask from which the spent nuclear fuel had been removed with expiration of the design lifetime were determined to be at very low levels, and the radiation exposure doses to which radiation workers were subjected during the decommissioning process appeared to be at insignificant levels. The evaluations of this study strongly suggest that the nuclide inventory of a spent nuclear fuel metal cask can be utilized as basic data when decommissioning of a metal cask is planned, for example, for the development of a decommissioning plan, the determination of a decommissioning method, the estimation of radiation exposure to workers engaged in decommissioning operations, the management/reuse of radioactive wastes, etc.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.357-365
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• 2016

We observed the ${\gamma}-ray$ shielding characteristics and compressive strength of five types of concrete using general aggregates and high-weight aggregates. The aggregates were classified into fine aggregate and coarse aggregate according to the average size. The experimental results obtained an attenuation coefficient of $0.371cm^{-1}$ from a concrete with the oxidizing slag sand (OSS) and oxidizing slag gravel (OSG) for a ${\gamma}-ray$ of $^{137}Cs$, which is improved by 2% compared with a concrete with typical aggregates of sand and gravel. In the unit weight measurement, a concrete prepared by iron ore sand (IOS) and OSG had the highest value of $3,175kg{\cdot}m^{-3}$. Although the unit weight of the concrete with OSS and OSG was $3,052kg{\cdot}m^{-3}$, which was lower than the maximum unit weight condition by $123kg{\cdot}m^{-3}$, its attenuation coefficient was improved by $0.012cm^{-1}$. The results of chemical analysis of aggregates revealed that the magnesium content in oxidizing slag was lower than that in iron ore, while the calcium content was higher. The concrete with oxidizing slag aggregates demonstrated enhanced ${\gamma}-ray$ shielding performance due to a relatively high calcium content compared with the concrete with OSS and OSG in spite of a low unit weight. All sample concretes mixed with high-weight aggregates had higher compressive strength than the concrete with typical sand and gravel. When OSS and IOS were used, the highest compressive strength was 50.2 MPa, which was an improvement by 45% over general concrete, which was achieved after four weeks of curing.

• Applied Biological Chemistry
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• v.49 no.4
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• pp.328-333
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• 2006

Many plant extracts are known to have antioxidative effects. However, their activities can be reduced or disappeared during mass production process. The purpose of this study is to compare antioxidative effects of edible plant extracts distributed in Korea. forty three kinds of edible plant extracts commercially available in Korea were selected and investigated for their total phenolics contents and antioxidative potentials(DPPH radical and superoxide anion radical scavenging activities). In contents of total phenolics, the commercial plant extracts from Artemisia annua(whole plant), Ilex paraguariensis(leaf, Silybum marianum(fruit and leaf, Ulmus pumila(bark), Coliolus versicolor(fruit), and Curcuma longa(root and stem) contained over 70 mg/g of powder, DPPH radical scavenging activities($SC_{50}$, 50% scavenging concentration) of A. annua, I. paraguariensis, Pinus densiflora(leaf),S. marianum, U. pumila, and C. longa were $53.96{\pm}0.81\;ppm,\;24.61{\pm}2.12\;ppm,\;35.96{\pm}1.11\;ppm,\;57.46{\pm}2.13\;ppm,\;55.25{\pm}1.65\;ppm\;and\;12.99{\pm}1.67ppm$, respectively, while that of positive control(vitamin C) was $3.86{\pm}0.81\;ppm$. $SC_{50}$ values against superoxide anion radical of A. annua, Cinnamomum zeylanicum(bark), I. paraguariensis, Rubus coreanus(fruit and leaf), Morus alba(leaf), P. densiflora, S. marianum, U. pumila, C. versicolor, C. longa, Perilla frutescens var. acuta(leaf), and H. sabdariffa(leaf and newer) were $53.21{\pm}1.83ppm,\;50.12{\pm}2.12ppm,\;5.59{\pm}0.84ppm,\;41.60{\pm}8.93ppm,\;20.19{\pm}0.97ppm,\;15.19{\pm}1.66ppm,\;21.20{\pm}1.88ppm,\;15.71{\pm}0.91ppm,\;55.48{\pm}2.42ppm,\;52.12{\pm}2.44ppm,\;23.80{\pm}1.98ppm\;and\;11.14{\pm}0.51ppm$, respectively($SC_{50}$ value of vitamin C: $9.61{\pm}0.93ppm$). In particular, both 1 paraguariensis and P. densiflora had high content of phenolics as well as high scavenging activities of DPPH radical and superoxide anion radical. Consequently, above two commercial extracts may be useful as a source of antioxidative nutraceutics.

• Applied Biological Chemistry
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• v.12
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• pp.89-97
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• 1969

These studies were made on coating of fresh fruits and vegetables with PVC under view on preservation of fresh fruits and vegetables due to restrain water evaporation of them and control gas metabolisms. The results obtained, as selection of PVC materials availble for preservation of them, procedure of the coating, useful organic solvents, concentration of PVC solution and the time of dipping, and effects of the preservation of them, were summarized as follows: 1) PVC powder 222 and PVC powder 443 were surveyed as suitable materials for coating apple, and later was excellent in lustrous aspect. 2) The coating procedure which dipt into PVC solution was suitable to treat much within a short space of time, and using of ventillator accelerate rather evaporation of the organic solvent. 3) Aceton and methyethylketon as solvent of the PVC were, in purpose of storage only, avaible, while aceton was, in view ef taste, better. 4) 10% of the PVC solutions were better to preserve the freshness of apple and 5, 4, 1 and 0.5% of them in order were gradually decreased in preservability, and 15% of them as high concentration were looked like fermentation in one week after the coating. 5) The dipping time was also better n minute than 10 seconds in a preservation but 1-2 minutes could be applied owing to be not affected of the taste due to coating. 6) The freshness of treatment groups were extend about 48 days after coating in room temperature but control lost market value with 12 days. 7) Weight of control was decreased to 10-13% but treatment which was dipped into 10% of coating solution for one minute was decreased to 3.5-4.6% and treatment for four minutes was did to 2.9-3.0%. 8) Change in respiration was less is treatment groups than control in exhaustion of $CO_2$, and water soluble sugar, reduced sugar and pH were not changed almost due to coating. 9) Pannel discussion of the taste was indicated that control was better than treatments soon after coating, but treatments were rather than control last period of storage and treatment with aceton solvent specially was better than others.

• Applied Biological Chemistry
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• v.13 no.1
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• pp.35-42
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• 1970

Five samples of Korean native Maeju(fermented soy-bean mash) loaves which were collected each from Kyunggi, Chungchung, Kangwon, Cholla and Kyungsang-Do were examined for their fermenting microorganisms. The results of taxonomic and ecological studies of fermentation microorganisms in these Maeju loaves were as the fellows. (1) The fungus flora grew only is the outer layer of Maeju loaves. Miscellaneous molds, 3 species of Mucor, 2 species of Pericallium., one species each of Scopulariopsis and Aspergillus, were isolated. None of them seemed exclusively predominant to be able to designate as the ecologically significant. (2) The bacterial flora which consisted of two species, Bacillus subtilis and Bacillus pumilus were distributed uniformly in th a entire Maeju loaves. The inner parts of Maeju loaves were especially inhabited solely by these bacterial flora. Probably the Korean native Maeju fermentation could be characterized by these bacterial flora. A Staphylococcus species was also isolated probably as a casual contaminant. (3) The yeasts, Rhodotorula flava and Torulopsis dattila, were isolated from Maeju loaves though their ecological significance was not clear. (4) The ecological aspects of fermentation microbes in the outer and inner parts of Maeju loaves were apparently different, consequently different fermentation processes might have occurred in these two parts and it brought quite different final outlooks in the final matured Maeju loaves. The outer part, rather rigid and dry, retained the light brown color of boiled soy-bean; whereas the inner part, soft and sticky, showed dark brown color indicating severe chemical changes. (5) The aflatoxin producing mold, Aspergillus oryzae was isolated from one sample among 5 of Maeju loaves. In addition to the low probability of isolability from Maeju loaves samples, since this mold grew only in the outer layer of Maeju loaves with such a low population density, about $10^4/g$, perhaps the aflatoxin problem in Korean native soysauce may not be critical.

• Applied Biological Chemistry
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• v.43 no.2
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• pp.86-94
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• 2000

In order to develop the enzymatic hydrolysis system concerned with taste and flavor, strains having the high hydrolyzing activity on the soy protein were selected from some traditional Mejus. Two molds and one bacterium producing enzymes which were different in character of hydrolysis were isolated and identified. Leucine and azodye enzyme activities of both M4 and M5 were relatively high among in the isolated molds. And, leucine enzyme activity of B16 was the lowest in the isolated bacteria. These strains were isolated as microorganisms having a dissimilar hydrolysis pattern on the soy protein by enzymatic reactions. Mold M4 on the culture solid media was mycelium colors of white and its sclerotia colors were changed from white to black. According to the result of slide culture, radial conidial head, subclavate vesicle, conidia of subglobose, stipes of uncolored with smooth walls and metula and phialides were existed. Because M4 was taxonomically similar to the characteristics of Aspergillus oryzae (ahlburg) species, M4 was identified and named as Aspergillus oryzae M4.Mold M5 showed white and black mycelium on the MEA medium. Mold M5 colony exhibited grayish-green color and have long(7 mm) sporangiophores at slide culture. Sporangia became brownish-gray and the wall of larger sporangia was broken to form small collars, and smaller sporangia were fomed continually from large basal membrane. Columella is globose and hyaline, and sporangiospores are ellipsoidal of small diameter$(80\;{\mu}m)$. Because M5 was taxonomically similar to the Mucor circinelloides of zygomycetes, M5 was was identified and named as Mucor circinelloides M5. Bacteria B16 colony was opaque white, circular and lobate, and had rod shaped endospore. B16 was found positive in stain, catalase, ${\beta}-glucosidse$ and V-P tests. B16 was found to utilize D-fructose, ${\alpha}-D-glucose$, maltose, D-mannose, D-raffinose, stachyose and sucrose. By the morphological and physiological results, the characteristics of B16 was thought to correspond to that of Bacillus megaterium. However, fatty acid composition was similar to Paenibacillus marcerans, requiring further study for the definite identification. Accordingly, Bacteria B16 was provisionally classified and named as Bacillus megaterium B16.

• Applied Biological Chemistry
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• v.8
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• pp.95-100
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• 1967

A quantitative study on the mercury residue in the brown rice of "Paldal", a recommended rice variety in Korea, was carried out by changing the date and frequency of application with different forms of organo-mercury fungicide(PMA), which is used for the control of rice blast. The results are summarized follows: 1) Mercury residues were higher with the emulsion formulation(0.21 ppm) than the dust formulation (0.16 ppm) when they were used for the control of leaf blast on July 13. 2) In case when both of the emulsion and dust formulations were used on July 13 and August 13, respectively, the mrecury residues were lower in the treatment on July 13 (0.216 and 0.16 ppm) than in the treatment on August 13 (0.304 and 0.238 ppm). 3) In an emulsion formulation was applied once on August 13, the mercury residue was 0.304 ppm and its application in twice on July 13 and August 13, the residue was counted 0.32 ppm. In case of dust formulation, the residues were observed 0.238 ppm in a single dose and 0.276 ppm in double application. 4) When the fungicide was applied to the rice plant on August 13, the mercury residues in brown rice, rice bran, and stalk and leaves were 0.304, 0.323, and 0.676 ppm, respectively found in the case of emulsion and in the case of dust formulation, they were 0.238, 0.283 and 0.698 ppm, respectively. The mercury residue, in general, were less in the case of dust than in the case of emulsion formulation and lowered by a single treatment than by two times application and it was also less by treating on July 13 than by treating on August 13.