Influences of four kinds of calcium salts on the functional performances of gelatin composite films

Abstract

Fish gelatin films were prepared with gelatin as the main raw material and four kinds of salts, including CaCl2, CaSO4, hydroxyapatite and Ca3(PO4)2, as the auxiliary reagents. The types of the anions and the concentrations of the calcium salts could affect the light transmission, swelling ratio, tensile strength, and elongation at break of gelatin films. The relationship between them was studied in this paper. The experimental data were analyzed and it is noted that the swelling ratio of the gelatin film was improved after adding the calcium salts. The swelling ratio of the hydroxyapatite/gelatin composite film was significantly bigger than that of other composite films. There is no significant effect on the light transmittance of the gelatin film after adding the calcium salts. The improved mechanical performances were found in the composite gelatin films by adding calcium chloride, calcium sulfate, and calcium phosphate. In comparison, calcium phosphate performed the greatest influence on improving the mechanical performances of the composite films.