Polymeric Complexes of Cornstarch and Waxy Cornstarch Phosphates with Milk Casein and Their Performance as Biodegradable MaterialsAuthor(s): Dorota Najgebauer | Tadeusz Grega | Marek Sady | Piotr Tomasik
Journal: Molecules ISSN 1420-3049
Volume: 9; Issue: 7; Start page: 550; Date: 2004;
Keywords: Anionic starch | biodegradable materials | intermolecular interactions | starch- casein complexes
Complexes of phosphated cornstarch and waxy cornstarch with casein were prepared and characterised. They were prepared from casein in defatted milk and corn and waxy corn starches phosphated to degree of substitution values (DS) of 0.0637 and 0.0968, respectively. The components were blended in starch to casein ratios of 2:1, 1:1, and 1:2, then precipitated with hydrochloric acid. Aqueous solubility, water binding capacity, IR spectra, and thermal analysis (thermogravimetry, TG, and differential thermogravimetry, DTG) of the precipitates revealed that they were not simple physical mixtures of the components. The components interact with one another electrostatically with involvement of the starch phosphate groups and the peptide bonds of casein as documented by the IR spectra. Because of their insolubility in 7 M aqueous urea solution they might also be considered as complexes in which the components were chemically bound. Enzymatic studies showed that they are biodegradable materials.