29-7 |
Physicochemical properties and fat binding capacity of water-soluble chitin |
J. E. SHIN, Q. Xu, and L. F. Chen. Dept. of Food Science, Purdue Univ., 1160 Food Science Bldg., West Lafayette, IN 47907-1160 Chitin and chitosan have been used in agricultural, food, industrial, and medical fields. However, chitin is not soluble in water and chitosan is only soluble in solution below pH 6.5. Various studies have been conducted to produce water-soluble chitin by chemical modification technique, but chemical modifications change the fundamental skeleton of chitin and chitosan and lose the original physicochemical and functional properties. It was hypothesized that random distribution of acetyl group in the chitin or chitosan molecules could solubilize chitin and chitosan in water at any pH. In addition, once the water-soluble chitin can be produced, its physicochemical properties of water-soluble chitin should be evaluated. Our objective was to characterize physicochemical and functional properties of water-soluble chitin produced by a twin-screw processor. Water-soluble chitin was produced from lobster shell, which was processed by deproteinization, demineralization and deacetylation with NaOH. The degree of deacetylation of chitin was determined by colloid titration. Molecular weight was determined by viscometric method. Viscosity was measured with a Brookfield viscometer. Fat binding capacity was determined by centrifugation. Our results showed that the degree of deacetylation of water-soluble chitin was from 50 to 70%. The molecular weight of our water-soluble chitin was from 105to 106, which was higher than most of commercial chitosan reported in literature. The viscosity of water-soluble chitin exponentially increased with its concentration. When various salts were added to water-soluble chitin solution, the viscosity decreased. Fat binding capacity of water-soluble chitin was from 300 to 400 %. These results suggest that both physicochemical and fat binding capacity of water-soluble chitin produced by twin-screw processor were similar to those of commercial chitosan. It maintains physicochemical and functional properties that are desirable in food and pharmaceutical applications. However, it has a definite advantage over commercial chitosan because it is soluble in any pH range.
Session 29, Carbohydrate
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