Chitosan is the second largest biopolymer in nature after cellulose. It is widely distributed and is mainly distributed in many lower animals, especially arthropods such as shrimp, crab, insects, etc., and also in lower plants. Such as bacterial algae and fungus in the cell wall.
Chitosan can be obtained by deacetylating chitin. When chitin is acted upon at 100 ° C and 40% NaOH, a deacetylation reaction is produced to obtain chitosan. This is a white or off-white translucent sheet-like solid that is insoluble in water and alkali and soluble in most dilute acids including formic acid, acetic acid and hydrochloric acid. The molecular structure of chitosan is similar to that of cellulose, except that an amino group (—NH 2 ) is attached at the C 2 position. Therefore, the affinity of the fibers in the paper is developed to form an ionic bond and a strong hydrogen bond. Moreover, the good film forming property of chitosan is beneficial to increase the surface strength of paper, and thus becomes one of the reinforcing agents for special paper.
Chitosan is in a powder state, tasteless, odorless, and the aqueous solution has some spicy feeling. The chitosan is added to the food, and is heated by a soup and a certain degree of frying, baking, and the like, and the structure is not changed. Under the protection of nitrogen, the decomposition does not occur when heated to 250 °C.
The chitosan powder was stored in a natural environment sheltered from sunlight at room temperature for 181 days, and there was no significant change in appearance, solubility, degree of deacylation, and the like. The chitosan-added biscuits were stored in a packaged state at a temperature of 40 ° C and a relative humidity of 75% for 80 days, and the dietary fiber and chitosan content in the sample did not change.
Physical and chemical properties of chitosan
