Preparation and Physiochemical Characterization of Bitter Orange Oil Loaded Sodium Alginate and Casein Based Edible Films

Biopolymers-based composite edible films are gaining interest in the food packaging industry due to their sustainable nature and diverse biological activities. In the current study, we used sodium alginate (SA) and casein (CA) for the fabrication of composite film using the casting method. We also added orange oil to the edible film and assessed its impact on the biological, chemical, physical, and barrier properties of the films. The fabricated films were analyzed using X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). It was observed that CA-SA films loaded with 1.5% OEO had better visual attributes, and a further increase in oil concentration was not found to be as favorable. Mechanical assessment of the films revealed that CA-SA-OEO (1.5%) film showed lower puncture deformation and higher puncture force values. XRD data showed that all samples exhibited peaks at similar positions (21 degrees of 2 theta) with different intensities. In FTIR analysis, characteristic peaks of the film components (sodium alginate, casein, and orange oil) were reported at corresponding positions. The thermal stability of films was enhanced after the addition of the OEO (1.5%), however, a greater increase in OEO caused a decrease in the thermal stability, observed during TGA analysis. Moreover, the surface of the blank CA-SA film (FL1) was found to be rough (with cracks) compared to CA-SA films (FL2) containing 1.5% OEO. Additionally, FL2 was found to be relatively better than the other samples in terms of swelling degree (SD), thickness, water solubility (WS), oxygen permeability (OP), water vapor permeability (WVP), moisture content (MC), and transparency (T).

Automated summary

Biopolymers-based composite edible films made from sodium alginate and casein were fabricated and orange oil was added. The study found that the addition of 1.5% orange oil improved the visual attributes and puncture force of the films, but further increase in oil concentration did not have a favorable effect on the properties of the films. XRD and FTIR analysis showed that all samples had similar peak positions and characteristic peaks. The thermal stability of the films was enhanced after the addition of orange oil, but a higher concentration caused a decrease in thermal stability. Films containing orange oil showed better surface smoothness, swelling degree, oxygen permeability, moisture content, and transparency.