Fully Biodegradable Edible Packaging Foils on the Basis of Potato Starch-Lipid-Protein Ternary Complexes

Fully biodegradable foils were prepared from potato starch, egg albumin, and either stearic or oleic acid. Foils prepared with oleic acid have higher tensile strength, relative elongation, thermal stability, and a more uniform macrostructure. Foils produced with stearic acid were characterized by a higher index of crystallinity than foils made with oleic acid. Functional properties of the foils can be modulated involving a sequence of blending of their components. The simultaneous blending of starch (10 weight parts of 5% aq. gel), albumin (1 weight part of liquid composed of 1 g of albumin in 7 mL of water), and stearic acid (5 weight parts of powder) provided the foil with the highest tensile strength (64.91 MPa/mm). Independently of the method of preparation, foils were white with a greenish-yellow shade. Analysis of the ATR-FTIR spectra showed that the macrostructure of the foils is built involving interactions between all three components.