Process for extracting chitosan from oyster shells

Abstract

The invention discloses a process for extracting chitosan from oyster shells. The process comprises the following steps: (1) washing: washing waste oyster shells with clear water to remove slit and impurities on the surfaces of the oyster shells; (2) drying: drying and pulverizing the oyster shells obtained in the step (1) to obtain oyster shell coarse powder; (3) low-temperature pulverizing: successively carrying out low-temperature freezing and low-temperature lyophilization on the oyster shell coarse powder obtained in the step (2), taking liquid nitrogen as a grinding medium, and carrying out low-temperature pulverizing by using an ultra-low-temperature pulverizer at the temperature from minus 80 DEG C to minus 120 DEG C; (4) carrying out high-pressure microjet ultra-fine pulverizing treatment to obtain paste slurry; (5) acid treatment: soaking the material obtained in the step (4) in diluted hydrochloric acid, washing until the material is neutral, centrifuging, and drying to obtain chitin; and (6) carrying out deacetylation, and drying to obtain the chitosan. The time of the whole process is shortened. In addition, black impurities cannot exist in an intermediate process, and the obtained product is white.

Description

technical field [0001] The invention relates to the technical field of marine biological activity extraction, in particular to a process for extracting chitosan from oyster shells. Background technique [0002] Chitosan is obtained by deacetylating chitin under strong alkaline conditions. Chitin, also known as chitin, was discovered by the French scholar Braconno in 1811, and was extracted from the crustacean shell by Odier in 1823, and named CHITIN, translated as chitin. Chitin is composed of N-acetyl-2-amino-2-deoxy-D-glucose linked by β-1,4 glycosidic bonds, which is the glycan of N-acetyl-D-glucosamine. Because chitin will take off part of the acetyl group during the production process, the commercialized chitin is a copolymer of N-acetyl-D-glucosamine and D-glucosamine. [0003] Chitin is the second largest biological resource after cellulose in nature. It is estimated that the annual biosynthesis of chitin is as high as 10 billion tons. It is one of the most abundant...

AI Technical Summary

Problems solved by technology

However, there are still some problems that cannot be ignored in the preparation of chitin from shrimp and crab shells. First, except for some large-scale seafood processing enterprises, shrimp and crab shells are difficult to purchase in a centralized manner. Generally, after being eaten by families or hotels, they are discarded as garbage. It is difficult to recycle; the second is that shrimp and crab shells contain a large amount of symbionts such as protein and fat, and the pretreatment is more troublesome. The treatment is not clean or completely dry, and it is easy to mold and deteriorate during storage.

It is because of such reasons that the full utilization of shrimp and crab shells is greatly restricted.

Chinese patent CN103936884A, a method for extracting chitin from shrimp and crab shells, is the applicant's prior application, but this method is not effective for processing oyster shell raw materials

Soochow University paper, Liu Hongxi, Extraction of oyster shell chitin and its derivatives in printing and dyeing, mentions the extraction of oyster shell chitin, but the focus is on the application of the obtained chitin in printing and dyeing, and its production process is Small laboratory tests, such as filtering with filter paper, many process steps and parameters are not suitable for industrial production