Binding Properties Of Regenerated Chitin Nanofibers

Chitin is a naturally occurring polysaccharide with poor solubility in water,common dilute acids,bases and organic solvents due to its high-molecular-weight and highly crystalline structure.Thus,direct application of chitin in the food industry is rather limited.Regenerated chitin nanofibers with good dispersibility can be prepared in a high yield by dissolving of chitin in cold concentrated phosphoric acid and regenerating in water.The binding properties of these regenerated chitin nanofibers were studied systematically in this study,which includes:(1)binding ability to p-carotene and application as p-carotene delivery carrier;(2)binding ability to cholesterol and cholic acid and anti-obesity effect;(3)binding ability to heavy metals and pigments.The first chapter of experiment described the binding ability to p-carotene and application as p-carotene delivery carrier.The binding of ?-carotene reached maximum at pH 6.0 and temperature of 25? with a shaking speed of 100 rpm for 6 h.The optimized binding occurred at a ?-carotene concentration of 0.3 mg/mL and a chitin concentration of 4 mg/mL.Simulated digestion experiments showed that 32%of ?-carotene was released in simulated gastric fluid and 61%of ?-carotene was released in simulated intestinal fluid.Since the absorption of ?-carotene mainly occurs in the intestinal region,the regenerated chitin nanofiber seems to be a good delivery carrier of it.The storage experiments of?-carotene binding on the regenerated chitin nanofiber indicated ?-carotene was more stable at 4? and at low concentration without light.Using ?-carotene concentration lower than the maximum binding ability of chitin nanofiber improved its storage stability significantly.The second chapter of experiment described the binding ability of regenerated chitin nanofibers to cholesterol and cholic acid and its anti-obesity effect.The optimized binding occurred at a cholesterol concentration of 1.2 mg/mL,cholic acid concentration of 1.4 mg/ml,and a chitin concentration of 6 mg/mL.Animal tests of anti-obesity effect were conducted with 100 mice randomly divided into five groups,which was feed with normal diet + water,high-fat diet + water,and high-fat diet + regenerated chitin nanofibers at the concentrations of 2,3 and 4 mg/mL,respectively.The body weights were recorded every three days,and the blood and liver homogenates were analyzed for biochemical markers after 60 days.The results demonstrated that the mice received regenerated chitin nanofibers treatments had lower body weight,lower level of triglyceride and cholesterol in blood,lower level of triglyceride and cholesterol in liver homogenate.Our finding indicate that regenerated chitin nanofibers have a good anti-obesity effect.In the last chapter of experiment,the regenerated chitin was employed as an adsorbent to remove heavy metals and pigments from water.The results demonstrated that that the equilibrium concentration of chromium and methylene blue was 0.04 mg/mL and 0.06 mg/mL,respectively at a chitin concentration of 4 mg/mL.The absorption of chromium was decreased with the increase of pH values.The adsorption of methylene blue were increased with the increase of pH.Our results demonstrated the excellent binding ability of regenerated chitin nanofibers,which may find potential applications in the aforementioned areas.