Mechanical, physical, and bio-functional properties of biopolymer films based on gelatin as affected by enriching with orange peel powder

Abstract

In the present study, bio-functional edible films were developed by incorporating different concentrations (0, 3, 6, 9, 12, and 15%) of orange peel powder (OPP) into the gelatin. The thickness, moisture content, and water vapor permeability of the gelatin films enhanced as the content of incorporated OPP increased. OPP-incorporated films showed lower L* value, but higher a*, b*, and opacity values. Films with higher concentration of OPP showed higher strengths and lower elongation properties. The surface and cross-sectional microstructure of films were also characterized by scanning electron microscopy. The antioxidant properties of films including total phenolic content, ABTS radical scavenging activity, and reducing power were significantly improved by enriching with OPP. The incorporation of OPP also increased the antimicrobial activity of gelatin films against Staphylococcus aureus and Escherichia coli. These results suggested that the orange peel has a good potential to be incorporated into gelatin to produce bioactive packaging films which will be helpful to maintain the quality of the packaged food products.