• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.392-396
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• 1995

Chitosan was prepared from red snow crab (Chinonecetes japonicus) under various conditions of deacetylation (NaOH concentration, heating temperature, heating time and intermittent and repetition treatment). By measuring the degree of deacetylation and the molecular weight (Mw), effect of preparation condition was studied. As the concentration of NaOH increased in deacetylation process, for chitosan treated over $40\%$ NaOH, the rate of increase of the deacetylation of chitosan decreased, but the difference of Mw decrease was nearly constant. When treatment temperature increased from $130^{\circ}C$ to $150^{\circ}C$, the deacetylation degree increased only $3^{\circ}C\;from\;84\%\;to\;87\%,$ but Mw decreased from 267,000 to 85,800. The difference of Mw decrease of chitosan treated $130-150^{\circ}C$ was larger than that with $90-130^{\circ}C$. The deacetylation degree and Mw of the chitosan prepared by continuous treatment for 3 hrs was$84\%$ and 267,000. On the other hand those of chitosan with intermittent and repetition treatment for 3hrs was $93\%$ and 28,000. In order to increase the degree of deacetylation and inhibit depolymerizing, the intermittent and repetition treatment was found to be more effective than the continuous treatment.

• KSBB Journal
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• v.9 no.2
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• pp.174-179
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• 1994

Chitin was isolated from crab shell wastes and characterized for its chemical and physical properties. White powdered chitin was obtained through demineralizaticn, deproteinization and decoloration process. The contents of inorganics was less than 0.5%, whereas protein and lipid were almost removed. The results of IR spectroscopic analysis for the isolated chitin showed similar characteristics with that of Sigma product. Degree of deacetylation of purified chitin was significantly higher than Sigma product and viscosity average molecular weights was $2.3{\times}10^5~3.2{\times}10^5$. SEM analysis showed that the obtained chitin had the fibril shaped morphology.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.395-398
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• 1999

Chitin was isolated from red snow crab (Chinonecetes japonicus) and deacetylated by boiling alkaline solution to produce chitosan. The physical properties of chitosan solution and its film properties was examined, As the molecular weights of chitosan was increased from 297Kpa to 319Kpa, the tensile strength, degree of elongation and water permeability of chitosan film were increased. As the degree of deacetylation of chitosan was increased, the tensile strength, the degree of elongation and water permeability of chitosan film were increased. As the concentration of chitosan solution was increased, the degree of elongation and water permeability of film were increased, whereas the tensile strength of film was decreased, As the pH of chitosan solution was increased, the tensile strength and water permeability of film were decreased, whereas the degree of elongation of film was increased.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.277-278
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• 2003

키틴은 셀룰로오스와 더불어 자연계에 가장 많이 존재하는 천연고분자(선형다당)로서 $\beta$(1$\longrightarrow$4)-2-deoxy-2-acetamido-D-glucopyranose를 기본단위로 하고, 키토산(chitosan)은 천연적으로는 몇몇 미생물에서 발견되며, 키틴의 탈아세틸화반응(deacetylation)에 의해 생성되는 유도체로서 $\beta$(1$\longrightarrow$4)-2-deoxy-2-amino-D-glucopyranose를 기본단위로 한다는 점에서 상이하다. 하지만 키틴과 키토산은 각 기본단위가 반복된 homopolymer가 아니고 서로 일정 정도의 상대 기본단위를 함유하므로 일종의 공중합체 또는 heteropolymer라고 할 수 있으며, 그 조성비 즉 탈아세틸화도 (degree of deacetylation, 이하 DD)에 따라 키틴과 키티산으로 나누어진다.[1] (중략)

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.558-563
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• 1999

Response surface methodology was used for monitoring physicochemical properties of chitosan with preparation of chitosan. Deacetylation degree of chitosan was in proportion to NaOH concentration for deacetylation of chitosan. The solubility of chitosan was maximized in 52% (concentration of NaOH), $109^{\circ}C$ (deacetylation temperature) and 123 min (deacetylation time). Viscosity of chitosan was mainly influenced by concentration of NaOH, and was greatly decreased with the increase of concentration of NaOH. The optimum condition ranges for preparation of chitosan was $52{\sim}54%$ NaOH, $100{\sim}115^{\circ}C$ in deacetylation temperature and $100{\sim}140\;min$ in deacetylation time.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.6
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• pp.807-818
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• 2004

The antibacterial activities of several types of chitosan were measured against Staphylococcus aureus and evaluated for their application to antibacterial textile finishing. The ％ reduction of bacteria of the chitosans prepared in our laboratory were between 72 and 87%. The two water-soluble chitosans with molecular weights 1,000 and 3,000 did not show antibacterial activities. The deacetylation of chitosan was appeared to increase antibacterial activity. The ％ reduction in bacterial density of the 86％-deacetylated chitosan solution was 56% where that of the 76％-deacetylated chitosan solution was only 17％ at 0.1% chitosan concentration. Molecular weights of the chitosans seemed not to affect antibacterial activities of chitosans. The antibacterial activity of the acid-soluble, 86%-deacetylated chitosan with 4 cps showed 98% of the ％ reduction at the level of 0.2％ chitosan. The ％ reduction of bacteria of this chitosan was higher at the higher concentration of acetic acid in the chitosan-bacterial mixture. The antibacterial activity was increased with the pH change over the range of 4.0 to 6.5. The 100% of the ％ reduction of bacteria was achieved within 4 hour incubation of the chitosan-bacterial mixture. According to the data obtained from the above experiments, the four chitosans among the six prepared in our laboratory were proved to be valuable for antibacterial textile finishing.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.95-96
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• 2001

수산식품의 품질검사를 위한 기존의 분석법들은 대부분 각종 무기 및 유기 시약을 이용한화학적 분석이 주로 이용되어지고 있으며, 이와 같은 화학적 분석 방법들은 시료의 전처리부터 최종 결과를 도출하기까지 상당한 시간이 소요되며, 분석자의 숙련도에 따라 결과의 재현성이 달라지는 단점들을 지니고 있다. 이에 비해 분광학적 분석 방법중의 하나인 근적외선(Near-Infrared) 분광분석법은 식품의 구성성분을 분석하는 비파과 측정법 중에서 가장 발전된 방법이라 할 수 있다. (중략)

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.19-23
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• 1999

Chitosan was partially degraded by using nitrous acid. The deacetylation degree of chitosan decreased with its degree of hydrolysis. Deacetylation degree of each fraction was less than 50%. The degraded product was fractionated by means of precipitation using aqueous methanol solution or aqueous methanol-acetone solution. The molecular weight of each fraction was distributed between 6000 and 4000, and below 2000 for being precipitated using aqueous methanol solution and aqueous methanol-acetone solution respectively. They had narrow molecular weight distributions, and their polydispersities were less than 1.7. The antibacterial activities for each fraction were evaluated against Bacillus subtilis HB 101 and E. coli PP 2, gram-positive bacteria and gram-negative bacteria, respectively. Fraction B (Mw=5100) showed high antibacteiral activity. All fractions were more active against Bacillus subtilis than E. coli.

• Polymer(Korea)
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• v.38 no.1
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• pp.85-92
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• 2014

To develop water-soluble chitosan as an effient gene delivery carrier, chitosan oligosaccharides (COSs) with various molecular weights (MW) were studied for gene transfection agents. MWs of COSs fractionated by ultrafiltration techniques were identified as narrow MW distributions with the average MW ranging from 1 to 10 kDa through gel permeation chromatography (GPC) measurement depending on the applied ultrafiltration membranes. Their structural characterizations were analyzed by FTIR spectrophotometer and $^1H$ NMR. The degree of deacetylation was determined by UV spectroscopy showing the degree of deacetylation above 90%. The relative cell viabilities were maintained over 100% (10 mg/mL), independent of the MW of the fractionated COSs. The fractionated COSs of 10 mg/mL concentration with narrow MW distributions showed non-cytotoxicity in Caco-2 cells.

• Polymer(Korea)
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• v.32 no.6
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• pp.544-548
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• 2008

The objective of this study is to obtain the anti-oxidant nanoparticles based on biocompatible polymers. It was chosen to conjugate with chitosan as the biodegradable polymer and lipoic acid as the hydrophobic anti-oxidant. Lipoic acid helps the regeneration of exogenous and endogenous anti-oxidants vitamin as well as glutathione and hence acts as antioxidant indirectly. Chitosan was prepared from chitin which was deacetylated under alkali solution for the various reaction time. Lipoic acid-chitosan complex was confirmed by $^1H$-NMR. The critical aggregation concentration was measured using pyrene and the values were about $5{\times}10^{-3}$ g/L. The particle shapes and sizes of the chitosan-lipoic acid nano-particles were about 135 nm that measured by DLS and TEM.