Investigation of Biodegradation and Physical Properties of PVA/Gelatin Film Incorporating Lemon Peel Extract and Rosehip Seed Oil

Growing environmental concerns regarding petroleum-based food packaging materials have accelerated the search for biodegradable alternatives. In this work, biodegradable films based on poly(vinyl alcohol) (PVA) and gelatin were produced via the solution casting technique and functionalized with lemon peel extract (LPE) and rosehip seed oil (RSO). The effects of polymer blending and natural additives on film thickness, antioxidant activity, water vapor permeability (WVP), and biodegradation behavior were examined. Blending gelatin with PVA caused only minor changes in film thickness, while the incorporation of lemon peel extract resulted in a slight increase from 0.108 mm to 0.115 mm. In contrast, the presence of rosehip seed oil significantly affected the film structure, increasing thickness up to 0.243 mm, corresponding to approximately a 125% increase compared with the gelatin film. The addition of RSO also improved the moisture barrier performance of the films. The WVP value decreased from 18.25 × 10⁻⁶ g·m⁻¹·s⁻¹·Pa⁻¹ for gelatin films to 6.23 × 10⁻⁶ g·m⁻¹·s⁻¹·Pa⁻¹ for RSO-loaded PVA/gelatin films,representing about a 66% reduction in water vapor permeability. Antioxidant activity was strongly influenced by the presence of plant-derived additives. The film containing both LPE and RSO reached 78.67% radical scavenging activity, indicating a substantial improvement in antioxidant capacity due to the presence of bioactive compounds. Soil burial experiments showed that gelatin films degraded rapidly, whereas PVA/gelatin-based films displayed a slower but still biodegradable degradation behavior. These findings demonstrate that combining polymer blending with natural bioactive additives can significantly improve the structural, barrier, and antioxidant properties of biodegradable packaging films.