• 한국식품영양과학회지
• /
• 제28권1호
• /
• pp.161-166
• /
• 1999

CaCl2 and water soluble degraded chitosan mixtures were used as coagulants for extending the shelf life of tofu. Microbial counts, pH, and turbidity in tofu immersion solution were analyzed during the periods of storage at 4oC and physico chemical properties of tofu were determined by rheological properties, color and yield. There was no significant difference in moisture content and yield between tofu made with and without chitosan. Failure stress and stress relaxation values were reduced when chitosan was added to CaCl2, but there was no significant change among contents of chitosan added to tofu. The pH values were decreased at the beginning and then slowly increased after 14 days storage. The changes in turbidity were increased during storage, but the change in 2.0g degraded chitosan mixture with 7.0g CaCl2 coagulant(2.0:7.0 ratio) was lower than others and initial turbidity was lower as much as chitosan added to coagulant. These data showed that the water soluble degraded chitosan had a good anti microbial effect and increases the shelf life of tofu.

• 한국식품과학회지
• /
• 제29권3호
• /
• pp.476-481
• /
• 1997

두부의 저장성에 미치는 수용성 키토산 분해물질의 영향을 알아 보기 위해 두부침지액으로 일반 시중 두부공장에서 사용하는 수돗물, 멸균증류수, 0.5% 키토산 분해물질, 0.5% fumaric acid, 0.5% lactic acid를 사용하여 $4^{\circ}C$에서 냉장저장하면서 pH와 탁도, 그리고 미생물상의 변화를 관찰하였다. 수용성 키토산 분해물질을 첨가한 침지액의 경우 총균수가 21일 저장시 $10^{7}\;CFU/mL$에 달해 다른 침지액에 비해 7일에서 14일의 저장기간 연장을 관찰할 수 있었다. 특히 초기 오염 미생물의 lag phase가 다른 군에 비해 상당히 길어진 것을 관찰할 수 있었다. Yeast와 mold, 그리고 E. coli의 경우도 시간이 경과됨에 따라 증가하였으며, 0.5% 키토산 분해물질 첨가 침지액의 경우가 다른 침지액의 경우보다 증가율이 적음을 알 수 있었다. 이는 수용성 키토산 분해물질의 항균효과를 잘 보여주고 있다. 초기 pH는 0.5% fumaric acid와 lactic acid의 경우 pH 4.68과 pH 5.12로 상당히 낮았으며, 수돗물과 멸균증류수, 0.5% 키토산 분해물질 첨가 침지액에서는 pH 7.2로 비슷하였고, 저장 초기에 약간 감소하다가 서서히 증가하는 경향을 보였다. 탁도의 변화는 미생물상의 변화와 연관시켜 두부가 부패된 것으로 간주되는 총균수 $10^{7}\;CFU/mL$이상에서 0.2를 초과해 탁도가 두부부패정도를 파악하는 한 척도가 될 수 있다고 판단된다. 상기 결과로부터 항균성을 가지는 수용성 키토산 분해물질을 첨가한 두부 침지액의 개발은 두부의 저장성 향상에 크게 기여할 것으로 사료된다.

• 한국식품영양과학회지
• /
• 제28권2호
• /
• pp.417-422
• /
• 1999

Algin and chitosan are known as biodegradable natural polymers. PVA is useful for the production of water soluble packaging, paper, textile sizes. PVA/Algin and PVA/chitosan films were prepared by solution blends method in the weight ratio of chitosan, algin for the purpose of useful biodegradable films. Thermal and mechanical properties of blend films such as DSC, impact strength, tensile strength and morphology by SEM were determined. As a result, The ratio of 10.0wt% PVA/chitosan films were similar to PVA at thermal and mechanical properties. PVA/Algin films were found that phase separation was occured as more than 25wt% increasing the blend ratio of algin. PVA/Algin films were observed to be less partially compatibility than 10wt% increasing the blend ratio of algin by DSC, mechanical properties and SEM. Blend films were completely degraded pH 4.0 better than 7.0, 10.0 in the buffer solution. Also, they were rapidly degraded in the enzyme( glucosidase) solution better than pH solution by enzymolysis.

• 한국응용과학기술학회지
• /
• 제15권3호
• /
• pp.21-26
• /
• 1998

Polyvinyl alcohol[PVA] is useful for the production of water-soluble packaging, paper, textile sizes. PVA and Chitosan are known as biodegradable polymers. PVA/chitosan blend films were prepared by solution blends method in the weight ratio of chitosan for the purpose of useful biodegradable films. Thermal and mechanical properties of PVA/chitosan blend films such as DSC, impact strength, tensile strength and morphology by SEM were determined. As a result, The ratio of 10.0wt% PVA/chitosan blend films were similar to PVA. Blend films were completely degraded pH 4.0 better than 7.0, 10.0 in the buffer solution. Also, Blend films were rapidly degraded enzyme(${\beta}-glucosidase$) solution better than pH solution by Enzymolysis.

• 한국염색가공학회지
• /
• 제12권3호
• /
• pp.166-173
• /
• 2000

Various kinds of water soluble N,N,N-trimethylchitosan ammonium chloride(TMC) with different molecular weights were synthesized to examine the antimicrobial activity against Methicillin Sensitive Staphylococcus aureus(MSSA) and Methicillin Resistant Staphylococcus aureus(MRSA), which causes serious hospital infection, and to apply them to antimicrobial finishing agents for textiles. Chitosan samples were highly deacetylated with sodium hydroxide solution and degraded with hydrogen peroxide to control the molecular weight. TMC has the antimicrobial activities against MRSA and MSSA. TMC showed an excellent antimicrobial activity below the molecular weight of 70,000, especially at 40,000. The minimum inhibitory concentration (MIC) of TMC with optimum molecular weight against MRSA and MSSA was 250ppm. Because MRSA did not resist TMC in the subculture test of bouillon medium, it was expected that the successive use of TMC against MRSA was possible.

• 공업화학
• /
• 제10권1호
• /
• pp.19-23
• /
• 1999

아질산염을 이용한 키토산의 부분가수분해 반응에서 반응이 진행됨에 따라서 탈아세틸화도는 감소하였으며 가수분해된 각 fraction에서의 탈아세틸화도는 50% 이하로 확인되었다. GPC를 이용하여 이들 각 유도체의 수평균분자량을 확인한 결과, 물-메탄올에 의한 침전물은 6000에서 4000의 분자량을 가지고 있었으며, 메탄올-아세톤에 의해서는 2000 이하의 분자량을 가지는 것을 얻을 수 있었다. 이때 다분산도는 1.7 이하로 분자량 분포가 좁은 분해물을 얻을 수 있었다. 각 fraction 별로 분자량에 따른 항균효과를 E. coli HB 101과 Bacillus subtilis PP 2에 대해서 시험한 결과 분자량이 5100인 fraction B($H_2O:MeOH=1:5$)가 가장 우수하였고, 모든 시료에서 그람양성균인 Bacillus subtilis PP 2에 대한 항균능이 그람음성균인 E. coli HB 101에 비해 우수하였다.