A new approach in the hydrophobic modification of polysaccharide-based edible films using structured oil nanoparticles

Abstract

This work aimed to study the effect of structured oil nanoparticles (SONs) for improving the hydrophobicity of polysaccharide-based edible films as a novel modification approach. SONs were fabricated from sunflower oil (SFO) using ethyl cellulose or monoglyceride as gelator. Farsi gum (FG) was selected as a model polysaccharide to develop edible films. The physicochemical, mechanical, thermal, and morphological properties of FG-based films incorporated with different concentrations (0%, 0.5 %, and 1% (w/w)) of SONs were compared with those of SFO-free (control) and SFO-incorporated FG films. Irrespective of the physical nature of added oil, the water vapor permeability, solubility, swelling ability, and surface hydrophilicity of FG films incorporated with SONs or SFO were significantly decreased. The SFO was more effective than the SONs in improving some hydrophobic properties; however, the flocculation of SFO droplets decreased the water vapor barrier properties. Incorporating SONs resulted in a compact and more uniform surface morphology, while a higher roughness and surface irregularity were observed after modification with SFO. The modified films prepared by incorporating SONs showed appropriate tensile strength and higher flexibility than control film, while those incorporated with liquid SFO droplets were too sticky and stretchy to be subjected to the tensile forces. The thermal stability of modified films was enhanced after incorporating SONs. The results indicated that the key properties of FG films were better improved by incorporating SONs than liquid oil droplets. Therefore, the SONs can be considered as an appropriate candidate for developing novel edible food packaging materials with high moisture barrier characteristics.