Development and Characterization of a Novel Ecofriendly Biodegradable Whey Protein Concentrate Film with nano-SiO2

Nowadays, researchers have attracted to substitute petroleum-based materials by biopolymers due to limitation of petroleum resources and environmental concerns. Nano-fillers were used to reduce some drawbacks of biopolymers as packaging materials. Nanocomposite films composed of 5% (wt% dry base) whey protein concentrate (WPC), 30% glycerol, (1%, 3%, and 5%) nano-SiO2 (NS). The films were prepared by solution casting method. Tensile strength of WPC/NS nanocomposites increased around 50% compared to WPC by increasing NS content up to 3%. While elongation at break (EB) decreased around 20% compared to WPC, simultaneously. But at high NS content (5%), EB decreased to 17.93%. Sensibility of WPC/NS nanocomposites film to water and water vapor permeability was decreased with increasing NS content up to 3%. NS content was an effective factor on the color properties of the films. SEM micrographs revealed uniform distribution of NS into polymer matrix at low NS content. Consequently, crystallinity and thermal properties of the film were improved by adding NS content as compared to WPC film. It seems NS can improve some drawbacks of WPC such as mechanical weakness, hydrophilic properties as a packaging material and allowing the development of biodegradable bionanocomposite.