effect of oleic acid on physical, mechanical and barrier properties of edible salep fil

new edible composite films formed from salep (orchis mascula) and 10%, 20%, and 30% (w/w) oleic acid were prepared by emulsification with the aim of improving the water vapor barrier and mechanical properties of the film. as oleic acid concentration increased up to 30% (w/w), oxygen permeability (27%), elongation at break (86%) and thickness (2%) of salep films increased significantly and the tensile strength (37%), solubility (39%), transparency (13%) and water vapor permeability (54%) decreased significantly (p<0.05). increasing the oleic acid concentration produced a slight yellowish color in the salep film, but it was still transparent in appearance. it was found that oleic acid can be incorporated into the film and might be applicable for food packaging applications that require high water vapor permeability.