Eco-friendly extraction and characterization of chitin and chitosan from the shrimp shell waste via microwave irradiation

Abstract

For the first time, the chitosan was prepared through a fast, easy and efficient method, by using a microwave irradiation in the three steps of the extraction: demineralization, deproteinization and deacetylation. A comparative study was performed by using the conventional heating method to prepare chitin and chitosan. The structure and physicochemical properties, especially the degree of deacetylation DD%, of the chitin and chitosan obtained by these two methods were characterized by Fourier-Transform Infrared Spectroscopy FTIR, Nuclear Magnetic Resonance spectroscopy NMR, X-ray Diffractometry XRD and Scanning Electron Microscopy SEM equipped with energy dispersion spectroscopy EDS. It was shown that chitosan, with a degree of deacetylation of 82.73%, was successfully prepared in 24 min via microwave irradiation method, while a much longer time of 6–7 h was needed for preparing chitosan with a same degree of deacetylation (DD = 81.5%), using a conventional heating method. The microwave technology has allowed a great reduction of the extraction time, about 1/16. These results revealed that microwave irradiation is a more energy saving, more efficient and environment-friendly way to valorize shrimp waste.