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physicochemical and functional properties of crawfish chitosan as ...

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ABSTRACT<br />

Chitosan is made from chitin by a chemical process involving demineralization (DM),<br />

deproteinization (DP), decolorization (DC), <strong>and</strong> deacetylation (DA). Very little work h<strong>as</strong> been<br />

done to demonstrate the effects <strong>of</strong> altering or excluding any <strong>of</strong> the processing steps on <strong>chitosan</strong><br />

characteristics. The present study w<strong>as</strong> undertaken to evaluate the effects <strong>of</strong> process modification<br />

during <strong>chitosan</strong> production on the physiochemical <strong>and</strong> <strong>functional</strong> <strong>properties</strong> <strong>of</strong> <strong>crawfish</strong><br />

<strong>chitosan</strong>s.<br />

Five experimental <strong>chitosan</strong> samples (DCMPA, DMCPA, DMPCA, DMPAC, DAMPC)<br />

prepared with modified processing protocols <strong>and</strong> the control (DPMCA - traditional <strong>chitosan</strong><br />

production process) were evaluated <strong>and</strong> compared with the two commercial crab <strong>chitosan</strong>s. All<br />

samples were subjected to <strong>physicochemical</strong> (moisture, nitrogen, <strong>and</strong> <strong>as</strong>h contents, degree <strong>of</strong><br />

deacetylation, molecular weight, viscosity, solubility, bulk density, <strong>and</strong> color) <strong>and</strong> <strong>functional</strong><br />

(water binding capacity, fat binding capacity, emulsion capacity, <strong>and</strong> emulsion viscosity)<br />

characteristic analysis. Three experimental replicates were performed with a duplicate analysis <strong>of</strong><br />

each sample.<br />

Results indicated that process modification <strong>of</strong> <strong>crawfish</strong> <strong>chitosan</strong> production yielded some<br />

differences on each characteristic compared with the control <strong>and</strong> commercial <strong>chitosan</strong>s. For<br />

instance, changing the sequence <strong>of</strong> DC for the production <strong>of</strong> <strong>crawfish</strong> <strong>chitosan</strong> affected its<br />

<strong>properties</strong>. DCMPA <strong>and</strong> DMCPA resulted in an incre<strong>as</strong>e in molecular weight <strong>and</strong> <strong>as</strong>h,<br />

respectively. In contr<strong>as</strong>t, DMPCA led to lower viscosity. The most notable change observed with<br />

the DMPAC <strong>chitosan</strong> w<strong>as</strong> a light brown degraded colored <strong>chitosan</strong> that exhibited <strong>properties</strong> <strong>of</strong> a<br />

weak polyelectrolyte. When <strong>chitosan</strong> process started with DA, a very poor <strong>of</strong> yield were<br />

obtained. When DM <strong>and</strong> DP were reversed during production, the results showed some<br />

vii

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