Aproveitamento racional de subprodutos da indústria pesqueira: Reação de desacetilação assistida por micro-ondas e condições de otimização utilizando Design Experimental Box-Behnken

Shrimp shells were used as a source of chitin. Chitin is a precursor to the chitosan biopolymer that has been used and studied in different areas of application. The aim of this work was the determination of parameters optimized in the experimental conditions established using Design Experimental Box-Behnken to obtain chitosan. Chitosan was obtained from the microwave-assisted chitin deacetylation reaction. Initially, the shells went through pretreatment stages: demineralization, deproteinization, and depigmentation to get purified chitin (PQ). The deacetylation reaction occurred by exposing the PQ to microwaves in an alkaline medium (NaOH). The determination of the degree of deacetylation (DD) of the product was performed through potentiometric titration. A fraction of chitosan was obtained by the conventional method (Qc), obtaining a degree of deacetylation of 62.6%. Another fraction was obtained by microwave radiation (Qm), obtaining DD above 70%. Within the experimental domain, the linear effects of all independent variables X1 (time), X2 (power) and X3 ([NaOH]) and the interactions X1 * X2 and X2 2 were statistically significant (p <0.05) for DD, time was the variable with the greatest influence.