Preparation and characterisation of food grade chitosan from housefly larvae

Abstract

The preparation and characterisation of food-grade chitosan from housefly larvae are reported. A refinement procedure was developed to remove larval mouth hooks from the primary chitosan product, which greatly improved the quality of the final product and simplified the production procedures. Different factors affecting chitosan preparation were studied and an orthogonal experiment was designed to determine optimal preparation conditions. When prepared under optimal reaction conditions, the end product was snow-white in colour, had a high deacetylation percentage, good viscosity, and a low ash content. The end product was characterised by Fourier transform infrared spectral analysis, X-ray diffraction analysis, thermo-gravimetric analysis, and differential scanning calorimetry. Its physical and chemical properties and sanitary index were determined and compared to the relevant Chinese standards. The results show that the chitosan we produced under optimal conditions meets the Chinese Fishery Trade Standard SC/T3403-2004 for food-grade chitosan.