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Recently, the design and production of biodegradable films have received special attention than synthetic packaging due to the reduction of environmental pollution. The aim of this study was to investigate the effect of Persian gums (1%) and gellan gum (1%) on the physical, mechanical and morphological properties of composite films based on sodium caseinate (10%) as film reinforcing agents. The films were synthesized by solvent evaporation and the effect of each gum on the characteristics of the composite films was evaluated. The results showed that the addition of gums strengthened the composite films. So that the composite films showed mechanical resistance and good barrier properties versus moisture and light. The surface properties and morphology of the films also showed that the gums were well computability to the casein film and formed uniform and stiff films. In addition, composite films had acceptable transparency. Thus, it can be concluded that the use of composite films and the combination of different polysaccharides with protein matrices can improve the properties of the resulting films. On the other hand, by adding antimicrobial and antioxidant agents to biodegradable films, they can be considered as active packaging.

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In this study, biodegradable packaging based on gelatin biopolymer (at a concentration of 3% w/w) containing nanoparticles of titanium dioxide (at a concentration of 1% w/w) and saffron extract (at a concentration of 2% v) by evaporation method was synthesized. In this study, physical properties (thickness, transparency, moisture content, solubility and water vapor permeability), mechanical, antimicrobial and antioxidant properties, structural and transparency properties of films were investigated. After analyzing the data, the results showed that the effect of saffron extract and titanium dioxide nanoparticles on all the studied properties was significant (P <0.05). Addition of titanium dioxide nanoparticles and saffron extract increased the thickness, improved the mechanical properties and reduced the moisture content, water vapor permeability, transparency, and solubility. Also, nanocomposite films containing titanium dioxide nanoparticles and saffron extract showed antioxidant properties (% 80%) and acceptable antimicrobial effects, especially against gram-positive Staphylococcus aureus bacteria. According to the results of this study, this type of packaging can be suggested as a suitable alternative to synthetic packaging.

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Today, the utilization of smart indicators in food packaging to monitor and detect food quality through analyzing quality data and color changes in packaging films based on the food's condition is on the rise. In this comparative study, halochromic films made of gelatin and k-carrageenan with mirabilis jalapa extract (6, 12, and 24%) and barberry extract (6, 12, and 24%) were developed and examined. Through SEM images and FTIR spectroscopy, it was observed that both types of films incorporating barberry and mirabilis jalapa extracts were uniformly dispersed in the gelatin and k-carrageenan polymer matrix, displaying notable molecular interactions like hydrogen bonding and electrostatic forces. However, films containing mirabilis jalapa extract exhibited more irregular and rough surfaces compared to those with barberry extract. Both types of films displayed good antioxidant properties and responsiveness to changes in pH and ammonia levels. Films with barberry extract demonstrated higher antioxidant activity and greater sensitivity to pH variations. The gelatin and k-carrageenan films with barberry and mirabilis jalapa extracts effectively indicated the freshness of lamb meat stored at 25°C by correlating with the presence of ammonia gases in the storage packages and pH fluctuations. Our results highlight that the structural, physical, and functional attributes of gelatin and k-carrageenan films incorporating pH-responsive extracts are significantly influenced by the extract type and concentration.