Edible Films Loaded with Orange Oil

The casting method was used to prepare casein (CA) and sodium alginate-based (SA) composite edible films loaded with orange oil (OEO). Initially, the CA solution (3% w/v) was made by mixing 3 g in 100 mL of distilled water (30 °C). The pH of the CA solution was adjusted to 5.6 using sodium hydroxide solution (2 N), and then it was stirred and heated at 85 °C for 10 min on a hot plate. The sodium alginate solution (3% w/v) was made by dissolving the SA in distilled water followed by heating (at 80 °C) and stirring for one hour. Both solutions (CA:SA) with a ratio of 10:1 were mixed for one hour at 80 °C, and the glycerol (2.5% w/v) was added. After this, the homogenous solution was mixed with OEO at 1.5, 2.0, and 2.5% concentration (v/v), followed by stirring (300 rpm) for one hour. The OEO loaded solution was kept at 25 °C for one hour to eliminate air bubbles [7 (link)]. After the formulation of a film-forming solution, it was cast in plastic Petri plates (90 × 15 mm) and dried at 25 °C for 48 h [4 (link)]. The films were peeled off from the surface of the Petri plates and stored in desiccators at 25 °C and 87% relative humidity. Before characterization, films were stored under the above-mentioned conditions for 12 h [9 (link)]. Table 1 shows the composition of the fabricated films. The experiment was repeated three times for the consistency of the results.