Effect of CaCl2 on the formation of Ca-induced starch aggregates and spherulitic structure in dried starch film

This study investigated structure-forming process of Ca-starch aggregates and CaCO3 in alkali-treated starch suspensions and dried films. It was found that the addition of CaCl2 in starch suspensions (pH 13.4) induced the formation of Ca-starch aggregates having different flow behaviors from the suspensions in the absence of CaCl2. Drying the Ca-starch suspensions at 43 degrees C to obtain dried starch films further induced the formation of CaCO3 spherulitic crystals (5-7 mu m) homogeneously embedded in the films shown by X-ray diffractometry and scanning electron microscopy. This study revealed the use of alkali-treated starches as the template for CaCO3 crystallization during dehydration.