Effect of chemical treatment duration on physicochemical, rheological, and functional properties of colloidal chitin

In this study, the physicochemical, rheological, and functional properties of colloidal chitin prepared from commercial shrimp shell α-chitin by acid hydrolysis at ambient temperature for various treatment durations were investigated. With increasing treatment duration, the functional properties viz solubility, water and fat binding capacity, and emulsion capacity increased significantly (p<0.05). Color of colloidal chitin had higher lightness values and whiteness index than commercial chitin (p<0.05), but were non-significant (p>0.05) among treatment durations. The degree of deacetylation decreased as treatment duration increased (p<0.05). The Carr index and Housner ratio showed that colloidal chitin powders had poor flowability. The colloidal chitin suspensions had rheothinning tendency, i.e., viscosities of the suspensions decreased with an increase in shear rate. These results suggest that colloidal chitin obtained in this study has better functional properties with enhanced whiteness index than commercial chitin, making it suitable for application as a functional ingredient in the food industry.