ANTIOXIDANT ACTIVITY OF ALGINATE POLYMER FILMS INCORPORATED WITH NANOEMULSION OF SCHINUS TEREBINTHIFOLIUS ESSENTIAL OIL

Objective: This study aimed to develop alginate polymeric films incorporated with nanoemulsion of Schinus terebinthifolius essential oil and evaluate their antioxidant activity against free radicals. Methods: The essential oil was extracted by hydrodistillation and characterized by GC-MS. Nanoemulsions were prepared by phase inversion method and incorporated into alginate films by casting. Antioxidant activity was assessed by the hydroxyl radical scavenging method using salicylic acid, with IC₅₀ values calculated for the biofilm and compared to positive controls (diclofenac sodium and aspirin). Results: GC-MS analysis revealed β-pinene (46.85%), α-pinene (18.55%), and germacrene D (17.06%) as the major constituents. The biofilm-nanoemulsion system exhibited moderate antioxidant activity, with an IC₅₀ value of 102.69 ± 3.12 mg/L. Although higher than the positive controls diclofenac sodium (IC₅₀ = 2.65 ± 3.97 mg/L) and aspirin (IC₅₀ = 11.00 ± 16.50 mg/L), the observed activity was attributed to the synergistic effects of monoterpenes (β-pinene and α-pinene) and sesquiterpenes (germacrene D and caryophyllene). Conclusion: The alginate films incorporated with nanoemulsion of S. terebinthifolius essential oil demonstrated moderate antioxidant activity, attributed to the synergistic effects of the major bioactive compounds combined with the controlled release provided by the alginate matrix. These findings indicate that the biofilm-nanoemulsion system represents a promising natural alternative for active food packaging applications to retard lipid oxidation and preserve food quality.