effect of oleic and stearic acids on the mechanical, water vapor permeability and microstructural properties of sodium caseinate films

the effect of oleic and stearic acids on the water vapor permeability (wvp) and mechanical properties of sodium caseinate films was investigated. emulsifiers (span 80 and 85) were employed to produce the base mixture of film. tensile strength (ts), elongation (e) and young's modulus (ym) were obtained for both standard (without lipids) and hydrophobic films. results showed that the addition of oleic and stearic acids caused a reduction in tensile strength and young's modulus, however increased elongation of films. the presence of lipid compounds decreased the water vapour permeability of film (about 50%). scanning electron microscope (sem) pictures emphasized the presence of stearic acid on the outer and inner side of film which is indicative of the decrease in wvp of the films.