• Applied Biological Chemistry
• /
• v.41 no.6
• /
• pp.442-446
• /
• 1998

Chitosan has been known to have an antimicrobial activity. Chitosan samples having different molecular weights were tested for the antimicrobial activity against Escherichia coli in a liquid medium and on the paper sheets coated with different types of chitosan samples. In a liquid medium, Chitosan A $(Mw\;3,000{\sim}5,000)$ and B $(Mw\;200,000{\sim}500,000)$ showed minimal inhibitory concentration (MIC) of 40 and $10\;{\mu}g/ml$, respectively. The MIC of chitosan C $(Mw\;500,000{\sim}1,500,000)$ was similar to that of chitosan B. The paper sheets coated with chitosan A, B, and C also showed growth inhibition against E. coli. As a typical agricultural product, strawberry was tested for the extension of shelf life by using the chitosan-coated packaging papers. Storage experiments showed that chitosan-coated packaging papers extended the shelf life of strawberry at the chilling temperature of $4^{\circ}C$.

• Proceedings of the Korean Fiber Society Conference
• /
• 2003.10b
• /
• pp.247-248
• /
• 2003

최근 환경과 건강에 대한 관심이 증대되면서, 염색 가공분야에 있어서도 환경오염을 일으키지 않으면서도 위생적인 쾌적성을 부여하는 가공이 큰 주목을 받고 있다 이러한 측면에서 황토와 키토산은 두 가지 요구를 모두 충족시킬 수 있는 훌륭한 천연소재이다. 본 연구에서는 황토 염색 전, 후에 키토산을 처리한 면직물을 이용하여, 키토산의 농도와 처리 조건에 따른 항균성 중진효과를 고찰하고자 하였다. (중략)

• Membrane Journal
• /
• v.6 no.1
• /
• pp.32-36
• /
• 1996

Acylated chitosan derivatives with several kind of acyl chain length were synthesized. Using trough, monolayers of the acylated chitosan derivatives were formed. Limiting area per glucose unit and temperature dependence of $\pi-A$ curves were determined. Multilayers were prepared by horizontal dipping method.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.23 no.2
• /
• pp.48-62
• /
• 1997

Chitosan oligosaccharides having aldehyde group at reducing end were prepared by oxidative-deamination reaction of chitosan by using sodium nitrite, and the resulting aldehyde group was reduced to 2, 5-anhydro-D-mannitol group. The obtained chitosan oligosaccharides showed an average degree of polymerization 2~3 by gel permeation chromatography analysis. It was highly soluble in hydrophilic solvents and thermally stable. N, N-diacyl, O-acyl chitosan oligosaccharides were obtained from the reaction between chitosan oligosaccharides and acyl chloried under dimethylaminopyridine. From differential scanning calorimetric measurement, N, N-dilauroyl, O-lauroyl chitosan oligosaccharides showed mesophase region, which was confirmed by polarized microscope as a thermotropic liquid crystalline state. X-ray diffraction pattern revealed that N, N-dilauroyl, O-lauroyl chitosan oligosaccharedes were highly crystalline, whereas chitosan oligosaccharides were not.

• Journal of the Korean Magnetics Society
• /
• v.16 no.1
• /
• pp.66-70
• /
• 2006

Magnetite nanoparticles, which have been extensively used in many fields, were encapsulated with a natural polymer, chitosan, to improve their biocompatibility. We have synthesized magnetite $(Fe_3C_4)$ nanoparticles using chemical coprecipitation technique with sodium oleate as surfactant. Nanoparticle size can be varied from 1.2 to 7.4nm by controlling the sodium oleate concentration. Magnetite phase nanoparticles could be observed from X-ray diffraction. Magnetic colloid suspensions containing particles with sodium oleate and chitosan have been prepared. High magnetic property chitosan-microsphere particles were prepared from oleate-coated magnetite suspension using spray method. The surftce, and tile morphology of the magnetic chitosan microsphere particles were characterized using optical microscope and scanning electron microscope. Magnetic hysteresis measurement were performed using a superconducting quantum interference device (SQUID) magnetometer at room temperature to investigate the magnetic properties of the chitosan microspheres including magnetite nanoparticles. The SQUID measurements revealed superparamagnetism of nanoparticles.

• Food Science and Industry
• /
• v.53 no.1
• /
• pp.69-83
• /
• 2020

For the development of the chitosan industry in Korea, the catch of red snow crabs caught on the east coast is rapidly decreasing. Therefore, it is urgent to develop raw materials that can replace the red snow crab as the top priority to solve the supply and demand problems, as well as wastewater treatment costs account for a large proportion of the cost of chitosan. In order to solve the problems, continuous research on biological extraction methods such as enzymatic extraction and microbial fermentation will increase production efficiency and lower unit cost as well as chemical extraction methods. Further efficient manufacturing method can be established. Establishing of novel techniques is indispensable for production of high-purity chitosan and the ability to regulate and separate the molecular weight, as well as joint research with industry, academia and research institute for the research and development of high-functional chitosan derivatives.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.4
• /
• pp.519-525
• /
• 2003

The effect of chitosan on antimicrobial effect, shelf-life, antioxidation, color, moisture content and pH of pork loins stored at 1$0^{\circ}C$ was investigated. All concentration of 5 kDa chitosan had very weak antimicrobial effect in all concentration against spoilage bacteria in meat. 30 kDa and 120 kDa chitosan had very strong those effects above 0.1%. The pork dipped in 1% of 30 kDa and 120 kDa chitosans extended a shelf-life. In antioxidation, the dipped pork has shown remarkable effects in all concentrations of 30 kDa and 120 kDa chitosans. Also, the external redness of them was maintained stably. Their moisture contents were decreased slightly with the higher molecular weight and concentration during storage. The results suggested that properties of porks were improved with dipping in 1.0% of 30 kDa and 120 kDa chitosan.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2003.04a
• /
• pp.99.1-100
• /
• 2003

키토산처리 콩나물에서 발아율이 높고 배축의 신장도가 높은 현상을 조사하기 위하여 전보에서와 동일한 방법으로 콩에 0.05% 키토산(493kDa, 금호화성, 한국)을 함유하는 0.05% 초산 용액 4배량을 가하여 8시간 침지한 후 2$0^{\circ}C$에서 2시간 간격으로 5일간 주수하면서 콩나물, 자엽, 배축으로 구분하여 전당, 환원당, 비환원당 및 유리아미노산의 함량변화를 조사하였다. 콩나물의 전당은 대조구, 키토산 처리구가 모두 성장에 따라 감소하였는데 대조구(1196$\longrightarrow$820 mg/100 g-f.w)보다 처리구(1241$\longrightarrow$670 mg/100 g-f.w)에서의 감소율이 높았다. 자엽의 전당함량은 성장에 따라 감소하였으며 키토산 처리구에서 현저하였고, 배축에서는 증가하는 경향을 나타내었다. 환원당 함량은 콩나물의 성장에 따라 감소하였으며 키토산 처리에 따른 뚜렷한 차이가 없었다. 그러나 자엽에서는 성장에 따라 감소하였으며 감소경향은 키토산처리구에서 높았다. 키토산 처리구에서 전당과 환원당의 감소율이 대조구보다 높은 현상은 키토산 처리에 의하여 생체 대사가 보다 활성화되기 때문이라 생각되며, 키토산처리에 의하여 발아율이 높고, 배축의 신장도가 높은 현상과 관련이 있는 것으로 판단된다. 유리아미노산은 재배 5일째 자엽과 배축의 유리아미노산 함량을 분석한 결과 aspartic acid의 함량이 가장 많았으며, 대조구의 경우 자엽에서는 25.4 mg/100 g-f.w, 배축에서는 88.2 mg/100 g-f.w이었다. 키토산처리구의 경우는 자엽에서는 23.12 mg/100 g-f.w, 배축에서는 120.18 mg/100 g-f.w이었다.높은 항 곰팡이 활성을 나타내었다. 이 외에도 황련의 물 추출물은 M. miehei 균주에서 우수한 항 곰팡이 활성을 나타내었다. 생약재의 70% Ethanol추출물을 농도별로 제조하여 항 곰팡이 활성을 살펴 본 결과, 70% ethanol추출물에서는 계피와 파고지, 초두구, 황련이 항 곰팡이 활성이 우수하였으며, 특히 계피의 70% ethanol 추출물에서는 5가지 균종에서 모두 우수한 항 곰팡이 활성이 나타났다. 균을 제외한 5가지 균종에서 높은 항균 활성을 보였으며, 이외에 생약재는 강황, 석곡, 황련, 호장근의 70% ethanol 추출물은 4가지의 균주에 대해서 항균 활성을 나타내었다. 또한 파고지, 오미자의 70% ethanol 추출물은 3가지 균주에 대해서 항균활성을 나타냈으며, 천궁, 육두구, 오수유, 갈근, 계피, 가시오가피의 70% ethanol 추출물은 2가지 균주에 대해 항균 활성을 나타내었다. 항균활성이 우수한 생약재를 농도별로 활성을 조사한 결과, 물 추출물과 10% Ethanol 추출물 모두 낮은 농도에서도 우수한 항균활성을 나타내었다.취와 함께 점질성 갈변물질이 생성되었다. 이와 같은 결과로 볼 때, BAAG의 처리는 BAAC의 경우보다 가격은 저렴하면서도 항균력은 우수한 천연 항균복합제재로써 농산물 식품원료에 적용하여 선도유지 기간을 연장할 수 있는 효과를 기대할 수 있었다. 과일 등의 포장제로서 이용할 가능성을 확인하였다.로 [-wh] 겹의문사는 복수 의미를 지닐 수 없 다. 그러면 단수 의미는 어떻게 생성되는가\ulcorner 본 논문에서는 표면적 형태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elemen

• Korean Journal of Food Science and Technology
• /
• v.36 no.4
• /
• pp.594-597
• /
• 2004

Effects of various levels and molecular weights (MWs) of chitooligosaccharides and chitosan with pork salt-soluble protein (SSP) on pH, moisture (%), viscosity, and hardness of protein-chitosan mixtures were determined in a model study. Mixtures of 0.15, 0.3, and 0.45% chitosan at various MWs (Low, 1.5 kDa; Medium, 30-50 kDa; High, 200 kDa) were dissolved in 3% SSP solution for measurement of pH and viscosity at $20^{\circ}C$. pH value increased with addition of 0.45% low MW of chitooligosacchearides into SSP (p<0.05), whereas decreased with addition of 0.45% medium MW and 0.3% or higher level of high MW chitosan. Viscosity increased with addition of more than 0.3% either medium or high MW chitosan (p<0.05), as compared to mixture with low MW chitolligosaccharide and control (p<0.05). No differences in gel pH, moisture, and hardness values were observed among treatments (p>0.05). Further study will be performed to evaluate rheological properties actual meat products with various levels and MWs of chitosan.

• Clean Technology
• /
• v.7 no.4
• /
• pp.281-290
• /
• 2001

A microwave-assisted process to prepare chitosan from natural crabshells has been investigated. This study was primarily to examine the effectiveness of microwave as clean energy for chitosan preparation. Several human-edible organic acids were used as clean catalyst, possibly to improve the current HCl-based hydrolysis process of polymeric chitosan. The microwave was found to be effective substantially in reducing the reaction time. Nonetheless, no beneficial effect of microwave other than time, such as the chemical selectivity, was hardly observed. The organic acids were very effective in the hydrolysis reaction of polymeric chitosan. Their catalytic behavior was greatly improved especially when reactions were performed under pressure. In the case of autoclave reaction for 60 minutes at $120^{\circ}C$, viscous solution of polymeric chitosan (mol. wt. > 300,000) turned into thin solutions of water-like viscosity, which means chitosan molecules were decomposed to very small-sized oligomers.