Effects of starch types on the properties of baked starch foams

Abstract

In order to determine how the physicochemical properties of starch foams depend on the type of the starch used in baking process, starch foams were prepared using native starch and selected starch derivatives. The morphology, the density, the water adsorption capacity, the impact strength, and the thermal properties were determined for foams made from native starch, pregelatinized starch, hydroxypropylated starch with different degrees of substitution (DS = 0.015-0.025 and DS = 0.1), low distarch phosphate, medium distarch phosphate, and two cationic starch types (DS = 0.027-0.029 and DS = 0.029-0.033). The modified starch foams exhibited a more expanded structure with thinner cell walls than the foam made from native starch. The density of the native starch was 0.21 g cm-3, while the density of the modified starch foams was lower, in the range of 0.14-0.17 g cm-3 except for the starch foam made from medium distarch phosphate. The thermal and physicochemical properties of the foams made from the other starch derivatives were dependent on the functional groups and the degree of cross-linking. The foam made from medium distarch phosphate had a significantly higher density and impact strength that was accompanied by a somewhat lower water adsorptivity. © 2013 Akadémiai Kiadó, Budapest, Hungary.