Phosphorylated and Cross-Linked Wheat Starches in the Presence of Polyethylene Oxide and Their Application in Biocomposite Films

Wheat starch is modified by phosphorylation and cross-linking. Starches are evaluated for phosphorus content, amylose content, swelling power, solubility, pasting properties, crystallinity, and morphology. Films are made with phosphorylated and cross-linked starches, and with addition of 10% (w/w) polyethylene oxide (PEO). The films are evaluated for morphology, water vapor permeability, mechanical properties, crystallinity, roughness, and angle of contact with water. Phosphorylated starch shows higher phosphorus content, amylose content, swelling power, and solubility than cross-linked starch and native starch did. The starch film containing PEO presents discontinuous morphology, is more crystalline and rugged, and less hydrophilic than starch films without PEO. The biocomposite proves promising for usage in flexible packaging.