METHOD OF PRODUCING TOTALLY-DESACETYLATED CHITOSAN WITH A HIGH MOLECULAR WEIGHT

摘要

The invention relates to a method for the at least partial desacetylation of chitin and/or chitosan. The inventive method comprises one or more steps consisting in boiling a suspension of chitin and/or chitosan in a concentrated soda solution at a temperature of less than or equal to 100 DEG C for a period of preferably between 20 and 30 min, said boiling being performed in a reduced pressure reactor in the absence of dioxygen. Moreover, each boiling step is preceded by a series of at least six freeze/thaw cycles, each of said cycles comprising the following steps consisting in: a) submerging the reactor in a cooling medium until the reaction medium is fully frozen; b) degassing the reactor such as to produce therein a pressure that is lower than atmospheric pressure; and c) gradually heating the reactor until the suspension has completely thawed.