The quality and safety of food products greatly depend on the physiochemical properties of the food packaging material. There is an increasing trend in the utilization of protein-based biopolymers for the preparation of edible films and coating due to their film-forming properties. Various studies have reported the preparation of protein-based edible films with desirable mechanical and barrier properties. The mechanical attributes of the protein-based food packaging materials can be enhanced by incorporating various components in the film composition such as plasticizers, surfactants, crosslinkers, and various bioactive compounds, including antimicrobial and antioxidant compounds. This review article summarizes the recent updates and perspective on the mechanical attributes such as Tensile Strength (TS), Elongation at Break (EAB), and Young’s Modulus (YM) of edible films based on different proteins from plants and animal sources. Moreover, the effects of composite materials such as other biopolymers, bioactive compounds, essential oils, and plasticizers on the mechanical properties of protein-based edible films are also discussed.

The aim of this study was to examine the effect of Sage (Salvia sclarea) essential oil (SEO) on the physiochemical and antioxidant properties of sodium alginate (SA) and casein (CA) based films. Thermal, mechanical, optical, structural, chemical, crystalline, and barrier properties were examined using TGA, texture analyzer, colorimeter, SEM, FTIR, and XRD. Chemical compounds of the SEO were identified via GC–MS, the most important of which were linalyl acetate (43.32%) and linalool (28.51%). The results showed that incorporating SEO caused a significant decrease in tensile strength (1.022–0.140 Mpa), elongation at break (28.2–14.6%), moisture content (25.04–14.7%) and transparency (86.1–56.2%); however, WVP (0.427–0.667 × 10⁻¹² g·cm/cm²·s·Pa) increased. SEM analysis showed that the incorporation of SEO increased the homogeneousness of films. TGA analysis showed that SEO-loaded films showed better thermal stability than others. FTIR analysis revealed the compatibility between the components of the films. Furthermore, increasing the concentration of SEO increased the antioxidant activity of the films. Thus, the present film shows a potential application in the food packaging industry.

Several studies have reported the advantages of incorporating essential oils in hydrogel-based films for improving their physiochemical and antioxidant attributes. Cinnamon essential oil (CEO) has great potential in industrial and medicinal applications as an antimicrobial and antioxidant agent. The present study aimed to develop sodium alginate (SA) and acacia gum (AG) hydrogel-based films loaded with CEO. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and texture analysis (TA) were performed to analyze the structural, crystalline, chemical, thermal, and mechanical behaviour of the edible films that were loaded with CEO. Moreover, the transparency, thickness, barrier, thermal, and color parameters of the prepared hydrogel-based films loaded with CEO were also assessed. The study revealed that as the concentration of oil in the films was raised, the thickness and elongation at break (EAB) increased, while transparency, tensile strength (TS), water vapor permeability (WVP), and moisture content (MC) decreased. As the concentration of CEO increased, the hydrogel-based films demonstrated a significant improvement in their antioxidant properties. Incorporating CEO into the SA–AG composite edible films presents a promising strategy for producing hydrogel-based films with the potential to serve as food packaging materials.

Aqueous extract of fruit obtained from Ficus racemosa enriched with phenolic components was used for the first time to fabricate chitosan (CS) and sodium alginate (SA)-based edible films. The edible films supplemented with Ficus fruit aqueous extract (FFE) were characterized physiochemically (using Fourier transform infrared spectroscopy (FT-IR), Texture analyser (TA), Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and colourimeter) and biologically (using antioxidant assays). CS–SA–FFA films showed high thermal stability and high antioxidant properties. The addition of FFA into CS–SA film decreased transparency, crystallinity, tensile strength (TS), and water vapour permeability (WVP) but ameliorate moisture content (MC), elongation at break (EAB) and film thickness. The overall increase in thermal stability and antioxidant property of CS–SA–FFA films demonstrated that FFA could be alternatively used as a potent natural plant-based extract for the development of food packaging material with improved physicochemical and antioxidant properties.

Gelatin (bovine/porcine)-based edible films are considered as an excellent carrier for essential oils (EOs) to preserve food quality and extend their shelf life. Spearmint essential oil (SEO) is known for its potential antioxidant and antimicrobial effects; nevertheless, its food applications are limited due to the volatile nature of its active components. Thus, edible films loaded with essential oil can be an alternative to synthetic preservatives to improve their food applications. In the present study, the effect of SEO addition was investigated on the physicochemical properties of bovine and porcine gelatin films, and antioxidant activity was assessed. GCMS (Gas chromatography mass spectrometry) analysis revealed the presence of carvone (55%) and limonene (25.3%) as major components. The incorporation of SEO into the films decreased the opacity, moisture content, water solubility, and elongation at break of bovine and porcine gelatin films. However, with the addition of EO, the thickness and water vapor permeability of bovine and porcine-based gelatin films increased. Moreover, the addition of SEO increased the tensile strength (TS) of the porcine-based film, whereas bovine samples demonstrated a decrease in tensile strength. XRD (X-ray diffraction) findings revealed a decrease in the percentage crystallinity of both types of gelatin films. SEM (scanning electron microscope) results showed the changes in the morphology of films after the addition of SEO. Antioxidant properties significantly (p < 0.05) increased with the incorporation of EO when compared with control films. Therefore, the addition of SEO to gelatin-based edible films could be an effective approach to prepare an active food packaging material to prevent food oxidation.

The essential oil extracted from Melissa officinalis (MOEO) exhibits a wide range of therapeutic properties, including antioxidant, antibacterial, and antifungal activities. The current research aimed to analyze the mechanical, barrier, chemical, and antioxidant properties of pectin and collagen-based films. Hydrogel-based films loaded with varying concentrations of MOEO (0.1%, 0.15%, and 0.2%) were prepared by solvent-casting method, and their physicochemical as well as antioxidant properties were examined. GC-MS analysis revealed the presence of major components in MOEO such as 2,6-octadienal, 3,7-dimethyl, citral, caryophyllene, geranyl acetate, caryophyllene oxide, citronellal, and linalool. Fourier transform infrared (FTIR) results revealed the interaction between components of the essential oil and polymer matrix. Scanning electron microscopy (SEM) revealed that films loaded with the highest concentration (0.2%) of MOEO showed more homogeneous structure with fewer particles, cracks, and pores as compared to control film sample. MOEO-incorporated films exhibited higher elongation at break (EAB) (30.24–36.29%) and thickness (0.068–0.073 mm); however, they displayed lower tensile strength (TS) (3.48–1.25 MPa) and transparency (87.30–82.80%). MOEO-loaded films demonstrated superior barrier properties against water vapors. According to the results, the incorporation of MOEO into pectin–collagen composite hydrogel-based films resulted in higher antioxidant properties, indicating that MOEO has the potential to be used in active food packaging material for potential applications.