Effects of two fatty acids on soy protein isolate/sodium alginate edible films: Structures and properties

The effects of chain length and concentration of different fatty acids (stearic acid and lauric acid) on the structure, physicochemical, and functional properties of soy protein isolate/sodium alginate films were assessed. Fourier transform-infrared spectra confirmed the presence of fatty acids within the films. Increasing the fatty acid chain length or concentration affected their uniform distribution, thereby increasing the opacity of the film modified with fatty acid. The concentration and type of fatty acid significantly affected the moisture barrier properties of the films. The films with stearic acid demonstrated higher hydrophobic characteristics and superior moisture barrier properties than other films. The films containing lauric acid exhibited higher elongation at break than those incorporating stearic acid. Scanning electron micrographs demonstrated insoluble particles and more roughness in the films incorporated with fatty acids. These results show that biopolymer-based films with required properties can be produced using appropriate fatty acids.