• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.437-438
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• 2007

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.9
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• pp.1249-1255
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• 2015

We examined the effects of selenium-binding peptide from sericin hydrolysates on the bioavailability of selenium-deficient rats. Three-week-old male rats were fed a selenium-deficient diet for 4 weeks while the normal control group was fed a normal diet. The selenium-deficient rats were divided into three groups: no treatment, organic selenium (OS), and inorganic selenium (IS). After selenium supplementation for 4 weeks, the level of serum glutathione reduced form in rats treated with organic selenium was significantly higher than that of inorganic selenium. Selenium retention rate also increased significantly in the organic selenium group compared to the inorganic selenium group [selenium deficient diet (DD)+OS 50.25% vs. DD+IS 17.04%, P<0.05]. In conclusion, binding of selenium to peptides from sericin hydrolysates seems to improve its bioavailability, and can hasten a cure for selenium deficiency in experimental rats.

• Membrane Journal
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• v.17 no.4
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• pp.375-380
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• 2007

To recover sericin protein from by-product in silk production process, a polyethersulfone hollow fiber ultra-filtration membrane module was used. The soap in the degummed solution was precipitated by calcium chloride. The influence of membrane module of submerged and external type on membrane fouling was investigated. The effect of soap and protein on the membrane fouling in the external type membrane module was also studied. The removal of soap resulted in decreasing the membrane fouling. It was shown that the protein and the membrane were affected by the soap.

• New & Renewable Energy
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• v.4 no.2
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• pp.39-44
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• 2008

Partial oxidation of methane was carried out by ceria-promoted Ni-substituted hydrotalcite-derived catalysts ($Ce_xNi_3$-HTlc ; x=$0.3{\sim}1.2$) in a fixed-bed reactor. The Ce/Ni ratio of 0.3/3 in the catalyst showed the best catalytic activity but the Ce/Ni ratio became higher above 0.3/3, the catalyst became less active in short-term tests. No ceria promoted catalyst was started to decrease $CH_4$ conversion after 20 h but the Ce/Ni ratio 0.3/3 catalyst was kept its stability in long-term tests.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.656-659
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• 2005

Nanocrystalline ceria powders were prepared by hydrothermal treatment of cerium(IV) ammonium nitrate solution without a precipitating agent. A systematic investigation of the effect of hydrothermal temperature and react ion time on the physical properties of the product powders was carried out. When the hydrothermal temperature was increased, the product ceria powders exhibited larger crystallite size with higher yield. Increasing reaction time produced more crystalline ceria powders attributed to further hydrothermal reactions and structural rearrangement. The physical properties of ceria powders can be control led by adjusting the hydrothermal conditions.

• Journal of Sericultural and Entomological Science
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• v.45 no.1
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• pp.34-45
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• 2003

Silk was treated with calcium hydroxide for degumming at different treatment times, temperatures and Ca(OH)$_2$ concentration to optimize degumming conditions in this thesis. After degumming, soluble and insoluble sericin were seperated and then the soluble sericin was characterized by measuring the average degree of polymerization (D.P.), lysinoalanine (LAL) content, DSC, and by amino acid analysis. And degummed silk fibroin was characterized by measuring tenacity and SEM. Degumming loss was increased by increasing the treatment time and temperature until about 30 minutes. After then, a slight difference was found along with treatment times at the Ca(OH)$_2$ concentrations of 0.07% and 0.1% solutions. After degumming, insoluble sericin ratio on degumming solution was increased by increasing treatment temperature at Ca(OH)$_2$ 0.04% solution. At the concentration Ca(OH)$_2$ of 0.07%, a soluble ratio was almost 100% regardless of treatment time and temperature. At the beginning of treatment, insoluble ratio was high at Ca(OH)$_2$ 0.1% solution but it was decreased by increasing treatment time. At the Ca(OH)$_2$ concentration of 0.04%, D.P. of soluble sericin was maintained as a constant value of 10 at 100$^{\circ}C$ although treatment time was increased. However, at 80$^{\circ}C$ and 90$^{\circ}C$, it was hard to prepare a soluble sericin having a constant D.P. by increasing treatment time. At the Ca(OH)$_2$ concentration of 0.07%, D.P. was almost 10 irrespective of treatment temperature and time. Soluble sericins with high D.P. of 20∼30 were obtained at 0.1% and 100$^{\circ}C$. LAL was not detected in soluble sericin. As the results of amino acid analysis, it showed that Ca(OH)$_2$ degumming reduced the contents of hydroxy amino acids like Ser., Thr. and Tyr. In DSC analysis of soluble sericin, endothermic peak by thermal deformation and pyrolysis showed at 189$^{\circ}C$ and at 299$^{\circ}C$, respectively. The tenacities of degummed silk were 15∼30% lower than that of raw silk. And it was decreased with increasing treatment time. From the morphological study, the thickness of degummed silk fibroin became thinner by increasing degumming loss. The roughness of a silk fibroin surface was appeared as treatment concentration was increased.

• Journal of Sericultural and Entomological Science
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• v.45 no.1
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• pp.46-57
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• 2003

This study was carried out to investigate the characteristics of the soluble sericins after degumming and after hydrolysis of insoluble sericin with various enzymes. Especially, the hydrolysis characteristics were examined in terms of molecular weight of the soluble sericin. Amino acid composition and molecular weight characteristics of the soluble sericins were also studied. When the insoluble sericin was hydrolyzed with kojizyme and flavourzyme, the solubility was highest at pH 7 and 50$^{\circ}C$. On the other hand, in the cases of protamex and alcalase, the highest solubility was obtained at 60$^{\circ}C$. In these cases, solubility increased with pH. In enzymatic hydrolysis, the solubility was increased with concentration of enzymes until 4 hours. After then, a slight difference was found along with treatment times. In enzymatic hydrolysis, the absorbance of the soluble sericin was increased with concentration of enzymes and treatment times. Average degree of polymerization was decreased with treatment time and concentration. The amino acid compositions were similar in low(low molecular weight by degumming) and high (high molecular weight by degumming). Those of PK (soluble sericin hydrolyzed with kojizyme), PP (soluble sericin hydrolyzed with protamex), and PA(soluble sericin hydrolyzed with alcalase) were similar to each other. Serine and tyrosine compositions were higher in low and high than those of PK, PP, and PA. However proline was absent in low and high. Molecular weights of the various sericins became higher as KP>high>PP>low>PA and those of KP and PA were 9,800 and 905 respectively.

• Journal of Sericultural and Entomological Science
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• v.40 no.2
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• pp.143-149
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• 1998

For the application of silk sericin, silk sericin powders were prepared by various spray dry conditions and the characteristics of silk sericin/polyurethane mixed films were investigated. When the sericin was dried from the solution at higher inlet and outlet temperature, larger sizes of the powder particles were obtained. It was also found that inlet and outlet temperatures were important factors affecting the shape and surface characteristics of sericin power particle. The many holes and empty spaces were observed at the surface and cross section of sericin/PU mixed film. With the increase of the amount of sericin powder in the mixed films, the size and number of holes and empty spaces were increased. The thickness of sericin/PU mixed film was increased with the content of sericin powder. As the portion of sericin powder increase, the tenacity is decreased while the elongation slightly increased.

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.257-260
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• 2008

• Textile Coloration and Finishing
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• v.21 no.1
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• pp.67-72
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• 2009

To investigate the strong and effective sericin fixing agents and conditions, raw silk fibers were treated with the mixtures of urea-formalin, thiourea-formalin and melamine-formalin as sericin fixing agents, respectively. And the treated raw silk fibers were degummed by the degumming liquors of alkaline detergent and sodium carbonate to confirm the hardness of sericin fixation. The weight of raw silk fibers was decreased in the process of sericin fixation treating at 80$^{\circ}C$ for 60min. The effective sericin fixation was obtained by treating at $60{\sim}80^{\circ}C$ for 15min with the mixture of melamine and formalin. The mixture of melamine and formalin showed an outstanding ability of sericin fixation because the three amino groups of melamine were able to cross-link the hydroxy amino acids of sericin such as serine with the assistance of formalin.