Chitosan is made from chitin by a chemical process involving demineralization (DM), deproteinization (DP), decolorization (DC), and deacetylation (DA). Very little work has been done to demonstrate the effects of altering or excluding any of the processing steps on chitosan characteristics. The present study was undertaken to evaluate the effects of process modification during chitosan production on the physiochemical and functional properties of crawfish chitosans.
Five experimental chitosan samples (DCMPA, DMCPA, DMPCA, DMPAC, DAMPC) prepared with modified processing protocols and the control (DPMCA - traditional chitosan production process) were evaluated and compared with the two commercial crab chitosans. All samples were subjected to physicochemical (moisture, nitrogen, and ash contents, degree of deacetylation, molecular weight, viscosity, solubility, bulk density, and color) and functional (water binding capacity, fat binding capacity, emulsion capacity, and emulsion viscosity) characteristic analysis. Three experimental replicates were performed with a duplicate analysis of each sample.
Results indicated that process modification of crawfish chitosan production yielded some differences on each characteristic compared with the control and commercial chitosans. For instance, changing the sequence of DC for the production of crawfish chitosan affected its properties. DCMPA and DMCPA resulted in an increase in molecular weight and ash, respectively. In contrast, DMPCA led to lower viscosity. The most notable change observed with the DMPAC chitosan was a light brown degraded colored chitosan that exhibited properties of a weak polyelectrolyte. When chitosan process started with DA, a very poor of yield were obtained. When DM and DP were reversed during production, the results showed some difference, e.g., the lower viscosity, higher fat binding capacity, and higher emulsion viscosity of DMPCA over DPMCA.
This study demonstrated that process modification of crawfish production affected physicochemical and functional properties. The optimal chitosan production may vary depending on the intended final usages in food systems as demonstrated by functional properties from this study.