• Journal of Adhesion and Interface
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• v.12 no.2
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• pp.73-80
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• 2011

In order to develop the environmental-friendly new materials based on soybean protein which is plantable macromolecule, thermal characteristics of the soybean protein resin (SPI) modified by plasticizers (1,3-propandiol, glycerol) and cross linking agents (glutaraldehyde, epichlorohydrin, glyoxal, urea) were analyzed by TGA. Mechanical properties of modified SPI were investigated and fracture was observed by SEM. As the result, flexibility of SPI film was increased by adding plasticizers; 1,3-propandiol and glycerol. Plasticization effect of glycerol was relatively greater than that of 1,3-propandiol. With the application of crosslinking agents (glycerol, epichlorohydrin and glyoxal), strength and thermal stability of SPI increased with their content. On the other hand, in case of addition of urea, thermal stability of SPI decreased and its strength was reduced because cross-linking between urea and SPI was somewhat difficult. Fracture surfaces and domain interfaces of the modified SPI resins were observed with SEM.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.3
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• pp.41-46
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• 1982

To elucidate the preservative characteristics of chestnuts, three varieties, Ungi, Okkang and Chuckpa, were stored in cellar, polyethylen film packing, and box with or without $\gamma-irradiation$, and chemical compositions, rates of sprouting and rotting were determined during the period of storage. The chemical compositions of raw chestnuts were: moisture, 59 to 63%; total sugar, 28 to 29%; reducing sugar, 0.1 to 0.2%; crude fiber, 0.6 to 0.9%; crude protein, 3.5%; vitamin C, 27 to 28mg%; and tannin, 50 to 58mg%. Total sugar and vitamin C were decreased during the period of storage, and of reducing sugar and tannin were increased. The rates after 6 months of storage after three vareitia were; 93 to 100% by the cellar storage; 35 to 57% by the box storage without $\gamma-irradiation$ and 1 to 4% with $\gamma-irradiation$; and none by the polyethylene film packing. The sprouting rate in Chuckpa decreased markedly as compared with the other two varieties. The rotting rates when stored for 6 months were: 4 to 6% by the box storage without $\gamma-irradiation$ and 7 to 12% with $\gamma-irradiation$; 5 to 8% by the polyethylene film packing; and 30 to 54% by the cellar storage. The rotting rate in Chuckpa was lower than the other varieties during the period.

• The Korean Journal of Food And Nutrition
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• v.21 no.2
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• pp.165-175
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• 2008

Pacific saury, Cololabis saira kwamaegi, is a traditional local food of the Eastern sea area centering around Pohang. It is well-recognized as being both tasty and nutritious. Nevertheless, bacterial contamination, excessive dryness, and compositional changes have made it edible only during the winter months. Therefore, to improve its storage, this study examined the effects of storage material, type, temperature, and duration on compositional changes in kwamaegi. The studied samples were kwamaegis that had been dried naturally for 15 days. The storage materials included an A-film, a self-developed multi-film made of polyethylene, polyamide, EVOH, and polyethylene; as well as a B-film made of polyethylene, nylon, polyethylene, nylon and polyethylene. The B films were used after pressing and laminating. The storage types included one whole fish(1G), or 2 divided fish(2G), to increase eating convenience. The 2G type was the muscle portion divided vertically after discarding the jowl, skin, and internal organs. The storage temperatures were $0^{\circ}C$, $-15^{\circ}C$, and $-30^{\circ}C$, and the storage durations were 2, 4, and 6 months. Pathogenic bacteria and rheology were measured to observe general compositional changes. The whole kwamaegi showed a total cell number of $1,565{\pm}112$ CFU/100 g flesh, while the divided Kwamaegi showed significantly greater bacterial numbers at $2,031{\pm}145$ CFU/100 g flesh. Psychrophils and halophils increased significantly while coliform were not found; the number of mesophils also increased, but not significantly. There were no significant cell number variations between the A-film and B-film. At $0^{\circ}C$, both the A-and B-films resulted in cell numbers of $115{\sim}212$ CFU/100 g flesh, revealing just $7.3{\sim}10.4%$ of the initial storage levels. Overall, there were no significant differences between the storage materials. Generally, as the storage temperature and duration increased, the moisture content of the kwamaegi decreased. Also, as storage duration and temperature increased, crude protein and crude lipid contents increased; in addition, they increased proportionally as the moisture content of the fish decreased. There were no significant differences in crude ash content with respect to the storage materials, storage temperatures, or storage durations. Finally, there were no significant differences between the kwamaegi samples naturally dried for 15 days and those stored in the B-film vacuum storage for 6 months for strength, hardness, cohesiveness, springiness, gumminess, and water activity.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.223.2-223.2
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• 2015

Polyurethane acrylate (PUA) has been introduced to utilize as a mold material for sub-100 nm lithography as it provides advantages of stiffness for nanostructure formation, short curing time, flexibility for large area replication and transparency for relevant biomedical applications. Due to the ability to fabricate nanostructures on PUA, there have been many efforts to mimic extracellular matrix (ECM) using PUA especially in a field of tissue engineering. It has been demonstrated that PUA is useful for investigating the nanoscale-topographical effects on cell behavior in vitro such as cell attachment, spreading on a substrate, proliferation, and stem cell fate with various types of nanostructures. In this study, we have conducted surface modification of PUA films with micro/nanostructures on their surfaces using plasma treatment. In general, it is widely known that the plasma treated surface increases cell attachment as well as adsorption of ECM materials such as fibronectin, collagen and gelatin. Effect of plasma treatment on PUA especially with surface of micro/nanostructures needs to be understood further for its biomedical applications. We have evaluated the modified PUA film as a culture platform using adipose derived stem cells. Then, the behavior of stem cells and the level of adsorbed protein have been analyzed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05a
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• pp.6-10
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• 2001

We synthesized polypyrrole (PPy) nanotubules by oxidative polymerization of the pyrrole monomer on the pore of a polycarbonate membrane. The electrochemical behavior was investigated using cyclic voltammetry and AC impedance. The redox potential was about -0.5 V vs. Ag/AgCl reference electrode, while the potential was about 0 V for electro-synthesized PPy film. It is considered as the backbone grows according to the pore wall. Therefore, it is possible to be arranged regularly. That leads to improvement in the electron hopping. The AC impedance plot gave a hint of betterment of mass transport. PPy nanotubules have improved in mass transport, or diffusion. That is because the diffusion occurs through a thin pore wall of PPy nanotubules. The kinetic parameter of PPy nanotubules enzyme electrode with glucose solution was evaluated. The formal Michaelis constant and maximum current calculated by computer were about 23.8 mmol $dm^{-3}$ and $440\;{\mu}A$ respectively. Obviously, an affinity for the substrate and current response of the PPy nanotubules enzyme electrode are rather good, comparing with that of PPy film. What is more, the enzyme electrode is sensitive to blood sugar of a diabetic serum despite an obstruction of ascorbic acid, oxygen, some protein and/or hormone.

• The Korean Journal of Community Living Science
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• v.17 no.3
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• pp.43-53
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• 2006

In order to improve on the stability during the storage of Han-gwa, this study measured peroxide value, AOM test of ginseng and antioxidants added to Han-gwa. 1.2% of ginseng added to Han-gwa consists of moisture (3.37%), protein(1.30%), lipids (11.54%), carbohydrate(82.45%) and ash (1.34%). The hardness of Han-gwa was 257.7 for 1.2% of ginseng added to Han-gwa and 269.8 for Han-gwa without ginseng. The expansion coefficient of Han-gwa including 1.2% of ginseng was 12.9 magnification to Bandegi, indicating that it was inversely proportioned to the amount of ginseng. The induction period of the AOM test according to the concentration of ginseng in Han-gwa was extended to $0.53{\sim}0.83$ of magnification than the test of Han-gwa without ginseng. According to changes in AOM, acid value, peroxide value and thiobarbituric acid value of Han-gwa with various packing materials, PP multilayer film packing was the most effective material for storage of Han-gwa at 30C. 1.2% of ginseng added to Han-gwa and rosemary extract in a panel test was the most effective, and using PP multilayer film packing for Han-gwa was found to be the most useful method.

• BMB Reports
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• v.34 no.5
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• pp.457-462
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• 2001

Using the monomolecular film technique, we compared the interfacial properties of Staphylococcus simulans lipase (SSL) and Staphylococcus aureus lipase (SAL). These two enzymes act specifically on glycerides without any detectable phospholipase activity when using various phospholipids. Our results show that the maximum rate of racemic dicaprin (rac-dicaprin) hydrolysis was displayed at pH 8.5, or 6.5 with Staphylococcus simulans lipase or Staphylococcus aureus lipase, respectively The two enzymes interact strongly with egg-phosphatidyl choline (egg-PC) monomolecular films, evidenced by a critical surface pressure value of around $23\;mN{\cdot}m^{-1}$. In contrast to pancreatic lipases, $\beta$-lactoglobulin, a tensioactive protein, failed to inhibit Staphylococcus simulans lipase and Staphylococcus aureus lipase. A kinetic study on the surface pressure dependency, stereoselectivity, and regioselectivity of Staphylococcus simulans lipase and Staphylococcus aureus lipase was performed using optically pure stereoisomers of diglycerides (1,2-sn-dicaprin and 2,3-sn-dicaprin) and a prochiral isomer (1,3-sn-dicaprin) that were spread as monomolecular films at the air-water interface. Both staphylococcal lipases acted preferentially on distal carboxylic ester groups of the diglyceride isomer (1,3-sn-dicaprin). Furthermore, Staphylococcus simulans lipase was found to be markedly stereoselective for the sn-3 position of the 2,3-sn-dicaprin isomer.

• Preventive Nutrition and Food Science
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• v.8 no.4
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• pp.343-348
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• 2003

To elucidate the effect of gamma-irradiation on the physicochemical properties of zein films, the molecular and mechanical properties of the films were examined after irradiation at various irradiation doses. Gamma-irradiation of zein solutions caused the disruption of the ordered structure of the zein molecules, as well as degradation, cross-linking, and aggregation of the polypeptide chains based on an SDS-PAGE study. Gamma-irradiation increased the solubility of zein and decreased the viscosity due to cleavage of the polypeptide chains. Protein solubility of the zein films in urea/2-mercaptoethanol also increased with increasing irradiation doses. Alterations of the zein molecules by irradiation decreased water vapor per-meability by 12% and increased the elongation of zein films. However, mean tensile strength of the zein films was decreased by gamma-irradiation treatment. Measurement of Hunter color values indicated that irradiation caused a destructive effect on yellow pigments, resulting in a significant decrease in Hunter b values. The microstructure as observed by scanning electron microscopy showed that irradiated zein film had a smoother and glossier surface than the non-irradiated films.

• KSBB Journal
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• v.22 no.6
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• pp.371-377
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• 2007

Polyhydroxyalkanoates (PHAs) are a family of microbial polyesters that can be produced by fermentation from renewable resources. PHAs can be used as completely biodegradable plastics or elastomers. In this paper, novel applications of PHAs in biosensor are described. A general platform technology was developed by using the substrate binding domain (SBD) of PHA depolymerase as a fusion partner to immobilize proteins of interest on PHA surface. It could be shown that the proteins fused to the SBD of PHA depolymerase could be specifically immobilized onto PHA film, PHA microbead, and microcontact printed PHA surface. We review the results obtained for monitoring the specific interaction between the SBO and PHA by using enhanced green fluorescent protein, red fluorescent protein, single chain antibody against hepatitis B virus preS2 surface protein and severe acute respiratory syndrome coronavirus surface antigen as model proteins. Thus, this system can be efficiently used for studying protein-protein and possibly protein-biomolecule interactions for various biotechnological applications.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.285-290
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• 2003

This study was conducted to select the bacteriocin-producing microoreanism cultivated in the rice bran culture and to characterize the produced bacteriocin for the further purpose of economical and anti-bacterial rice bran protein film. Pseudomonas putida 21025 was cultivated from rice bran and identified as a producer of a bacteriocin which showed bactericidal activity against Pseudomonas aeruginosa 9027. Bacteriocin produced by Pseudomonas putida 21025 showed a broad spectrum of activity against spoilage and soil bacteria. The activity of the bacteriocin produced by Pseudomonas putida 21025 decreased after 1 hr of staying at the temperature of $50^{\circ}C$, and with the presence of some organic solvents, except hexane and ethanol. However, the bacteriocin activity was stable throughout the pH ranges of 6-9 for 2 hrs, at the temperature lower than $50^{\circ}C$, and with the presence of ethanol for 3 hrs. The bacteriocin was partially purified by 50% ammonium sulfate precipitation followed by subsequent dialysis. Direct detection of the partially purified bacteriocin on SDS-PAGE suggested that it had an apparent molecular mass of about 21.6 kDa.