• Journal of Microbiology and Biotechnology
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• 제22권2호
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• pp.256-263
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• 2012

A strain of bacterium producing antifungal antibiotic was isolated and identification of the strain was attempted. We could identify the bacterium as being a Bacillus sp., based on morphological observation, physiological characteristics, and 16S rDNA sequence analysis, thus leading us to designate the strain as Bacillus sp. AH-E-1. The strain showed potent antibiotic activity against phytopathogenic and human pathogenic fungi by inducing mycelial distortion and swelling and inhibiting spore germination. The antibiotic metabolite produced by the strain demonstrated excellent thermal and pH (2-11) stability, but was labile to autoclaving. From these results, we could find a broader antifungal activity of Bacillus genus. Isolation and characterization of the active agent produced by the strain are under progress.

• 미생물학회지
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• 제18권4호
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• pp.161-171
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• 1980

A mutant strain having increased productivity of both enzymes, protease and amylase, was obtained from A. flavus KU 153, isolatd from South Korea for its high protease production by successive ultra-violet light irradiation, Two glucoamylases from the mutant strain selected were purified from wheat branculture by successive salting out, followed by dialysis and column chromatography, and their characteristics were compared with those of the wild strain. Glucoamylase production of the mutant selected was increased about 3.3 times compared with the wild strain, and 2.1 times compared with the parental strain, ${\alpha}-amylase$ activity of the mutant selected was about 2 times hugher than that of the wild strain or the parental strain. Protease and cellulase productivities of the muant selected were all alike compared with those of the highly proteolytic mutant, the parental strain. Therefore, it was considered that the back mutation on the protease production did not occurred in the formation process of the glucoamylase producing mutant. Total activities of glucoamylase I and II from the mutant selected were 2.86 and 3.65 times higher compared with those from the wild strain, respectively. Considering the optimal pH-thermal stability and Km-Vmax value of glucoamylase I and II from both strains, wild and mutant, it was deduced that the characteristics of glucoamylase I and II from the wild strain did not altered during the mutation process. Therefore, it was concluded that the selected mutant did not induce the formation of another glucoamylase isozyme, or the changes in the characteristics of the glucoamylase, but induce the productivity of the same glucoamylase I and II by the action of regulatory gene.

• 대한핵의학회지
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• 제24권1호
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• pp.49-55
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• 1990

For the development of $^{99m}Tc-labelled$ 3-iodo-2,4,6-trimethyl-iminodiacetic acid $(^{99m}Tc-IOTIDA)$, various experiments such as synthesis of IOTIDA, establishment of labelling conditions, determination of radiochemical purity, examination of stability, and organ distribution of rat were carried out. 1) IOTIDA was synthesized with a total yield of 42% from the starting material of 2,4-6-trimethylaniline via chloroacetylation, iodination, and condensation with iminodiacetic acid (IDA). 2) Freeze-dried instant labelling kits were prepared from aqueous solution $(pH\;5.8\sim6.0)$ so as to contain 40 mg IDA compound and 0.4 mg $SnCl_2$, per vial. Labelling of the contents of kit vials with $Na^{99m}TcO_4$, exhibited formation of two kinds of complex which was identified by ITLC-SA. After labelling, complex ( I ) was gradually converted to complex (II) with time. Labelling yield and radiochemical purity were above 99.5% based on the two complexes over-all. 3) $^{99m}Tc-IOTIDA$ maintained high radiochemical purity of above 99% until 6 hours after preparation at room temperature. Instant labelling kits stored at $4^{\circ}C$ for 6 month period also exhibited high labelling yield of above 99%. 4) Results obtained from animal experiments showed that most of the $^{99m}Tc-IOTIDA$ was rapidly excreted through hepatobiliary track into the intestines but with negligible renal excretion.

• 한국식품과학회지
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• 제49권4호
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• pp.396-400
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• 2017

본 연구는 홍국 분말 첨가수준에 따른 유화형 소시지의 이화학적 특성에 대하여 조사하였다. 수분함량은 홍국분말 첨가량이 증가할수록 유의적으로 높아지는 추세를 보였으며, 단백질함량과 지방함량은 감소하는 경향을 보였다. 색도는 홍국 분말 첨가량에 따라 명도와 황색도는 감소하는 반면 적색도는 크게 증가하였다. 가열감량, 수분리, 유분리와 점도는 홍국 분말 첨가량이 증가함에 따라 감소하는 경향을 보였다. 관능평가에서 색도와 다즙성은 홍국 분말 3% 첨가 처리구가 유의적으로 가장 높은 값을 나타내었고, 풍미는 홍국분말 2~3% 첨가 처리구가 유의적으로 가장 높은 값을 나타내었다. 연도는 홍국 분말 첨가 처리구가 대조구보다 높은 값을 보였으며, 전체적인 기호도에서는 홍국 분말 2% 첨가 처리구가 가장 높은 값을 나타내었다. 연구결과를 종합하면 돈육 유화물에 홍국분말을 첨가하여 제조하였을 때 홍국 첨가에 따른 적색도가 증진되어 육색을 개선시키는 효과가 있으며 이화학적 품질특성을 향상시키는 것으로 생각된다.

• 한국식생활문화학회지
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• 제30권1호
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• pp.77-85
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• 2015

This study investigated the physicochemical properties and antioxidative activity of soymilk added with buckwheat sprout (SBS), and sensory properties of SBS were analyzed with control soymilk (CS). Moisture content decreased while protein, ash, and lipid contents increased according to content of buckwheat sprout. Solids content and viscosity tended to increase with addition of buckwheat sprout from 0% (CS) to 2.5% (2.5SBS), 3.5% (3.5SBS), and 4.5% (4.5SBS). SBS was found the significant pH drop from 7.08 to 6.43, 6.34, and 6.21. Suspension stability of soymilk slightly decreased with addition of buckwheat sprout. Hunter's color value L of SBS decreased while a and b values increased in comparison with CS. Rutin content was measured 23.78 mg/100 g (2.5SBS), 39.68 mg/100 g (3.5SBS), and 44.80mg/100 g (4.5SBS). Vitamin C content in SBS was higher than CS. Daidzin content increased as buckwheat sprout was added. Total phenolic content increased from 100.95 mg/100 g (CS) up to 315.71 mg/100 g (4.5SBS). For free radical scavenging activity, SBS was significantly higher than CS. In conclusion, SBS can be used as a functional food with higher amounts of rutin, vitamin C, total phenolics, and daidzin. 2.5SBS and 3.5SBS also showed better overall quality characteristics.

• 한국식품과학회지
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• 제30권4호
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• pp.948-956
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• 1998

전통안동식혜의 제조법을 계승 보존하고 제조 공정 및 상품성을 높여 보다 우수한 가공식품으로 개발할 목적으로 안동식혜의 발효에 관여하는 젖산균과 효모를 분리한 균주를 이용하여 안동 식혜를 제조하여 숙성 및 저장 과정 중 성분과 품질의 변화를 조사하였다. 전통안동식혜로부터 분리동정된 균주는 젖산 균주로써 L. bulgaricus LBS 47, L. acidophilus LAS 10 및 Lacto. lactis LLS 56의 3 균주와 효모 S. cerevisiae SCS 5의 한 균주를 분리하여 단독 및 혼합 균주를 start로 사용하여 숙성시킨 후 관능검사를 한 결과 LBS와 SCS 균주를 혼합배양하였을 때 가장 좋았다.

• Food Science and Biotechnology
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• 제14권3호
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• pp.317-322
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• 2005

A simple and convenient method of immobilizing dextransucrase via an affinity interaction is described, along with the use of this system to synthesize leucrose. Dextransucrase was produced in sucrose-free medium by fermenting a constitutive mutant of Leuconostoc mesenteroides NRRL B-512F and was separated using an ultrafiltration membrane. The purified enzyme was free of dextran polymer, which previously was always found with the sucrose-induced enzyme. Therefore, it was possible to immobilize the enzyme on dextran-based resins using an affinity interaction. Sephadex G-200 was the best resin for immobilizing the dextransucrase and gave a fast flow rate through the packed column. The immobilized dextransucrase retained more than 80% of its specific activity after immobilization ($K_m\;=\;18.1\;mM$ and $k_{cat}\;=\;450\;sec^{-1}$ vs. 13.1 mM and $640\;sec^{-1}$, respectively, for the free enzyme). The immobilized dextransucrase showed improved stability over a pH range of 4.0 to 6.5 and at moderately high temperatures over $40^{\circ}C$. When immobilized dextransucrase was used to synthesize leucrose via the transfer reaction with sucrose and fructose, about 74% of the sucrose was converted into leucrose after one day, and the half-life of the enzyme activity was 15 days. Regeneration of the resin by supplementation with dextransucrase enabled the recovery of the initial activity of the system, but both the reaction and the flow rate were lower, probably owing to the accumulation of dextran inside the resin.

• 한국식품과학회지
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• 제32권2호
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• pp.284-290
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• 2000

한천분해능이 뛰어난 해양세균 Bacillus cereus ASK202를 사용하여 최적조건 하에서 배양실험을 행한 결과, 배양시간 30시간 경과시에 최대량의 한천분해효소가 생산되었으며, 그 생산량은 160.8 unit/L로 기존에 보고된 다른 균주들에 비해 한천분해효소 생산능이 뛰어남을 확인하였다. 또한, 생산된 한천분해효소를 이용하여 기질인 한천과 반응시킨 결과, 주로 중합도 2, 4, 6의 올리고당이 생성됨을 확인하였다. 그리고, 한천올리고당의 물리 화학적 특성을 기존의 제품화된 각종 올리고당과 비교 분석한 결과, 고점성, 높은 올리고당의 함유율, 뛰어난 내산 내열성, 저 감미도를 확인하였다.

• 방사선산업학회지
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• 제5권1호
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• pp.21-24
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• 2011

This study was conducted to evaluated the sensory properties of Miyukgook, Korean seaweed soup, with gamma-irradiated Undaria pinnadifida for enhancing the storage of the harvested seaweed. The harvested seaweed was irradiated at the doses of 1, 3, 5, and 10 kGy. The Miyukgook was made by following the general recipe. The values of pH and acidity of the Miyukgook were not changed by the irradiation of harvested Undaria. The sensory evaluation result showed that the preference scores in all the sensory properties was a little decreased when it was irradiated, but sensory score of less than 5 kGy samples was similar in all terms. Therefore, it was considered that gamma irradiation with less than 5 kGy was effective for improvement of the storage stability of U. pinnatifida without the changes in the sensory of its major cooked food, Miyukgook.

• Geomechanics and Engineering
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• 제7권2호
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• pp.183-200
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• 2014

The expansivity of clayey soils is a complicated phenomenon which may affect the stability of geotechnical structures and geo-environmental projects. In all common factors for the monitoring of soil expansion, less attention is given to anion type of pore space solutions. Therefore, this paper is concerned with the impact of various concentrations of different inorganic salts including NaCl, $Na_2SO_4$, and $Na_2CO_3$ on the macro and microstructure behavior of the expandable smectite clay. Comparison of the responses of the smectite/NaCl and smectite/$Na_2SO_4$ mixtures indicates that the effect of anion valance on the soil engineering properties is not very pronounced, regardless of the electrolyte concentration. However, at presence of carbonate as potential determining ions (PDIs) the swelling power increases up to 1.5 times compared to sulfate or chloride ions. The samples with $Na_2CO_3$ are also more deformable and show lower osmotic compressibility than the other mixtures. This demonstrates that the barrier performance of smectite greatly decreases in case of anions with the non-specific adsorption (e.g., $Cl^-$ and $SO{_4}^{2-}$) as the salinity of solution increases. Based on the results of the X-ray diffraction and sedimentation tests, the high soil volumetric changes upon exposure to carbonate is attributed to an increase in the repulsive forces between smectite basic unit layers due to the PDI effect of $CO{_3}^{2-}$ and increasing the pH level which enhance the buffering capacity of smectite. The study concluded that the nature of anion through its influence on the re-arrangement of soil microstructure and osmotic phenomena governs the hydro-mechanical parameters of expansive clays. It seems not coinciding with the double layer theory of the Gouy-Chapman double layer model.