Valorization of Mediterranean Aromatic Plants for the Production of Functional Films for Food Applications

The growing concern about the environmental impact of petroleum-based plastics has intensified the search for sustainable alternatives in food packaging. In this context, active biodegradable films incorporating plant-derived bioactive compounds have attracted considerable attention as materials to improve food quality. This study investigated the potential of using extracts from six Mediterranean Diet herbs – mint, coriander, rosemary, basil, thyme, and oregano – in functional food packaging films. Extracts were prepared using a natural deep eutectic solvent (NADES) of choline chloride and lactic acid (1:2) and compared with methanol. The extracts were evaluated for total phenolic and rosmarinic acid contents and antioxidant capacity using ORAC and ABTS assays. In parallel, the film-forming performance of various biopolymers, including sodium alginate, chitosan, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, gelatin, soy protein, and carob germ, was evaluated. The resulting films were characterized in terms of their optical properties, water swelling behaviour, puncture resistance, rheological properties, and antioxidant capacity. NADES was consistently more efficient than methanol, yielding 1.4- to 6.6-fold higher total phenolic contents. Oregano showed the highest values, reaching 90.11 ± 1.67 mg_GAE/g_DW, with antioxidant capacities of 132.71 ± 1.10 and 371.73 ± 1.53 mg_TE/g_DW by the ABTS and ORAC assays, respectively. Among the biopolymers evaluated, hydroxyethylcellulose exhibited the best overall performance, producing transparent, flexible, and structurally stable films. Incorporation of plant extracts into hydroxyethylcellulose films increased antioxidant capacity in a concentration-dependent manner, reaching a 3.8-fold enhancement at 50% (w/w, based on dry polymer weight), without significantly compromising mechanical behaviour. These findings highlight NADES-assisted extraction of Mediterranean herbs combined with hydroxyethylcellulose as a promising and environmentally friendly strategy for developing active food packaging materials. Future studies will evaluate the antimicrobial efficacy and performance of these films in real food systems to assess their potential for extending shelf life.