• Journal of Nutrition and Health
• /
• v.30 no.7
• /
• pp.751-769
• /
• 1997

This study was performed to investigate the effect of chitosan and NOCC from different sources and of different molecular weights on cadmium toxicity. Sprague-Dawley rats were blocked into 26 groups according to body weight, and were raised for 4 weeks. Cadmium chloride was given at the level of 0 or 400 ppm in diet. Various forms of chitosan and NOCC were given at the level of 0 or 4%(w/w) of diet. Cd toxicity was alleviated by various chitosan and NOCC supplements. However, the alleviating effects were different with fiber source(crab and shrimp), type(chitosan and NOCC), and molecular weight (low, medium, and high). Molecular weight had no significant effect. Compared with shrimp-source-fiber-fed groups, crab-source-fiber-fed groups showed lower Cd concentrations in blood and kidney, lower kidney metallothionein concentration, and lower liver and kidney MT-Cd contents. Compared with NOCC -fed groups, chitosan-fed groups showed lower intestine and liver Cd concentrations, lower liver and kidney MT concentrations and MT-Cd content, and higher fecal Cd excretion. Among cadmium-exposed group, low molecular weight shrimp chitosan group showed low Cd concentrations of liver and kidney, high fecal Cd excretions, and the lowest intestine and liver MT concentrations and liver MT-Cd content. In summary, a crab source fiber was more effective than shrimp source fiber, chitosan was more effective than NOCC, and the most effective one in alleviating Cd toxicity was low molecular weight shrimp chitosan.

• Fashion & Textile Research Journal
• /
• v.5 no.5
• /
• pp.529-538
• /
• 2003

Chitosan should be satisfied a certain Mw range for the final application, Low molecular weight chitosan(LMWC) can be acquired by depolymerizing high molecular weight starting chitosan. Using $H_2O_2$ in depolymerizing chitosan is very effective and reproducible in controlling Mw of resulting LMWC. However, $H_2O_2$ can break glycoside linkage of chitosan and oxidize some $-NH_2$ groups in chitosan. It has been reported that decrease in DA(degree of deacetylation) of LMWC prepared by $H_2O_2$. However, any quantitative data of decrease in DA has not been reported yet. In this study, DA of initial chitosan and DA of $H_2O_2$ treated chitosan were measured and the change in DA of chitosan upon $H_2O_2$ treatment were investigated. Change in DA was very different upon $H_2O_2$ treatment condition. LMWC also showed DA change upon time passage. Pre-swelling treatment of initial chitosan and low ratio of $H_2O_2$/chitosan prevented a decrease in DA significantly. Yellowing of LMWC was detected upon time passage, however, decrease in DA was minimal (around 1%).

• Korean Journal of Veterinary Research
• /
• v.43 no.4
• /
• pp.703-708
• /
• 2003

This study was carried out to compare the efficacy of carboxymethyl chitosan fabric (CMCF) with that of the combination of low molecular weight heparin (LMWH) and CMCF for the prevention of postoperative adhesions in the rat. Adhesions were induced by suturing both the ileal serosa and peritoneum scraped until petechial bleeding occurred. CMCF were sutured between two surfaces, and LMWH were instilled intraperitoneally immediately before closure of the peritoneomuscular layer. The adhesions were blindly assessed 2 weeks later by using a tensiometer. The mean tensile strength(Newton) of formed adhesions was $2.59{\pm}0.85$ in control group, $2.10{\pm}0.75$ in the CMCF group and $1.53{\pm}0.44$ in the CMCF+LMWH group. The most favorable prevention against adhesion was achieved in the CMCF+LMWH group. Therefore, we could conclude that CMCF+LMWH were effective in prevention against postoperative adhesion in the rat.

• Textile Coloration and Finishing
• /
• v.23 no.2
• /
• pp.90-99
• /
• 2011

The aim of this study is to develope eco-printing method using natural pigments and chitosan as a natural binder. Three chitosans with different molecular weights were employed to find appropriate conditions including chitosan concentration and pigment/binder ratio. Dye uptake, color and fastnesses of the printed fabrics were evaluated to find optimum conditions within the range of experiments carried out in this study. The effectiveness of chitosan as a printing binder was examined in comparison with color, dye uptake, and fastnesses of conventional synthetic binder and guar gum. It was found that chitosans with low or medium molecular weight were appropriate. Using low molecular weight chitosan, optimum concentrations were 1.7% for charcoal, madder and chlorophyll, whereas 2.2% for ocher, yellow soil, indigo and cochineal. Regardless of molecular weight and concentration of chitosan, the color fastnesess of fabrics printed with mineral pigments were superior to those of the fabrics printed with plant and animal pigments. As pigment/chitosan ratio became higher, rubbing fastness was decreased by 1-3 grade. The colorfastness of printed fabric with chitosan binder was similar to that with synthetic binder, which was higher than that with guar gum.

• Journal of Environmental Health Sciences
• /
• v.24 no.3
• /
• pp.48-53
• /
• 1998

Chitin is known as biodegradable natural polymer. But, in spite of various application of chitin from waste marine sources, commercial use of chitin has been limited due to highly resistance to chemicals and the absense of proper solvents. We made various viscosity of chitosan from chitin by change of Mima's method through the deacetylation which is various condition of NaOH concentration, reaction time and temperature. Also, Polyvinyl alcohol/chitosan blend films were prepared by different solution blends containing the ratio of 5, 10, 15 and 20% chitosan and low, medium, high molecular weight of chitosan to find a more useful biodegradable polymer. Thermal and mechanical properties of PVA/chitosan blend films such as DSC, impact strength, tensile strength and morphological changes by SEM were determined. The 10-15% PVA/chitosan(low, medium) blend films were similar to PVA. Also, PVA/chitosan blend films at the laboratory soil test(Pot Test) were completely degraded in month with four kinds of soils by microorganisms.

• Journal of Nutrition and Health
• /
• v.30 no.7
• /
• pp.770-780
• /
• 1997

This study was performed to investigate the effect of chitosan and NOCC from different sources and of different molecular weights on lipid metabolism. Sprague-Dawley rats were blocked into 26 groups according to body weight, and were raised for 4 weeks. Cadmium chloride was given at the level of 0 or 400 ppm in diet. Various chitosan and NOCC sources were given at the level of 0%(w/w) of diet. Total serum cholesterol and serum triglyceride concentrations were little affected by chitosan and NOCC supplements. However, HDL-cholesterol concentration and HDL : total cholesterol ratio were increased , and liver lipid, cholesterol , and triglyceride concentration were decreased by chitosan and NOCC supplements. The cholesterol and lipid lowering activity depends on fiber sources(crab and shrimp); type (chitosan and NOCC); and molecular weight(low , medium , and high). Among cadmium-free groups, chitosan-fed groups showed greater activity than NOCC -fed groups in lowering cholesterol and lipid levels, and greater fecal excretion of lipids and bile acids. Crab chitosans were more effective in cholesterol and lipid lowering activity than shrimp chitosans. The group fed high molecular weight crab chitosan showed the highest fecal excretion of lipids and bile acids. This indicated that high molecular weight crab chitosan was most effective in interfering with cholesterol and lipid absorption.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.2
• /
• pp.277-282
• /
• 2001

The effects of chitosans with two different molecular weights (150 and 37 kDa) on the clarification of persimmon vinegar were investigated. The coagulated solids increased with increasing chitosan concentrations. Chitosan treatment had no effect on pH and acidity. Turbidity, browning, contents of tannin and soluble solids decreased with increasing chitosan concentrations. An increase in chitosan concentration resulted in an increase in color L* value and a decrease in a* and b* values. Reduction in turbidity and tannin contents somewhat differed depending on the molecular weights of chitosan. In sensory evaluation, chitosan treatment did not affect color and flavor over all concentrations tested. However, astringent taste was noticeably strong by treatment with 500mg/L chitosan, resulting in low overall acceptability. Therefore, the most effective clarification of persimmon vinegar was achieved by treatment with 400mg/L chitosan, irrespective of molecular weight.

• Journal of Pharmaceutical Investigation
• /
• v.28 no.3
• /
• pp.151-158
• /
• 1998

The inhibition rate of bacteria growth per molecular weight was higher according as the molecular weight increased, the rate was the highest at the molecular weight 200,000. Microcapsule of ionized calcium was able to be produced by molecular weight 15,000, 30,000, 50,000 and 200,000 of chitosan which was dried for 48 hours after melting it in 2% of acetic acid, adding ionized calcium and controlling pH 1.2. The size of ionized calcium microcapsule was between 200 and $300\;{\mu}m$, the solvency, concentration and the content showed big difference by the molecular weight of chitosan. The inhibition rate of bacteria growth of microcapsule designated high in Gram positive, which was high in S. aureus, S. epidermidis and Bacillus subtilis, low in S. mutans, high in C. albicans in fungi, low in A. niger. The inhibition rate of bacteria growth of chitosan was comparatively high in Gram positive, low in S. mutans and it showed high numerical value in C. albicans of fungi. The rate recorded good result at molecular weight 200,000 relatively, there was no difference according to the molecular weight. The inhibition rate of bacteria growth according to the concentration of the microcapsule increased differently between $1.000{\sim}10,000\;{\mu}g/ml$, it showed antibacterial activity close to the inhibition rate of growth of chitosan rather than ionized calcium. The minimum inhibitory concentration marked the highest in the mixture of chitosan and ionized calcium for all kind of bacteria generally, there was a little difference between yeast and fungi.

• Preventive Nutrition and Food Science
• /
• v.10 no.3
• /
• pp.224-230
• /
• 2005

The effects of low viscosity chitosan on the rheological properties of soymilk using a model system and on tofu qualities were examined. The flow behavior of soy milk with chitosan closed the Newtonian flow and stabilized according to increasing chitosan concentration. The soymilk containing $glucono-\delta-lactone$ exhibited a more pseudoplastic flow behavior compared with that of the control soymilk. The addition of low viscosity chitosan to the tofu preparation did not significantly affect its physicochemical properties. However, the results of the TEM image and instrumental textural properties showed that low viscosity chitosan affected the construction of the tofu structure. Chitosan tofu had low scores across the whole field of appearance in the sensory evaluation, and its overall eating quality was scored significantly lower. These results suggest that the addition of low viscosity chit os an affects the quality of tofu, which changes according to the degree of polymerization and concentration of chitosan.

• Korean Journal of Food Science and Technology
• /
• v.42 no.6
• /
• pp.688-692
• /
• 2010

The aim of this study was to investigate the effects of molecular weight and concentrations of chitosan on the germination of brown rice. Brown rice was germinated at $30^{\circ}C$ for three days in various chitosan solutions. The germination rate of the brown rice increased with increasing concentrations of chitosan solution, and was higher in the chitosan solution than in water. GABA content increased with increasing germination time and chitosan solution concentration. As the molecular weight of the chitosan decreased, germination rate and GABA content increased in the brown rice. The GABA content of germinated brown rice using low molecular weight chitosan A in a 100 ppm solution was 5145.5 nmole/g. This is approximately a five times higher value than that of the water-germinated brown rice. Texture properties were enhanced in all the germinated brown rice samples in chitosan solution compared to the brown rice germinated in water. These results indicate that chitosan solution treatment can increase germination rate and GABA synthesis activity in brown rice during germination, and can also improve the texture properties of brown rice.