Natural extracts have been used in several traditional medicine applications and culinary purposes. Their biological properties (antioxidant and antimicrobial) are due to the presence of several active aromatic compounds. Herein, different natural extracts were evaluated, namely structural and thermal characterization and biological activity, in its natural form and incorporated into a polymeric matrix, to assess their effective potential as additives for active food packaging. While rosemary presented the highest thermal stability with a degradation starting at 327°C, lemon balm extract was the less stable (180°C). Regarding the thiobarbituric acid assay, all extracts presented antioxidant activity, in oxidative hemolysis inhibition; anise, cinnamon, and clove extract did not present any action. Overall, the results demonstrated that leaves (rosemary and green tea) and the rhizome (curcumin) are the plant parts with the best performance. Therefore, extracts from aromatic plants are promising natural additives that can be incorporated into polymeric matrices to produce active food packaging film, increasing products shelf-life.
The authors acknowledge the financial support by Portugal 2020, and Fundo Social Europeu (FSE) through Programa Operacional Regional do NORTE (NORTE-08-5369–FSE-000034), developed under the program “IMPULSE - Polímeros e Compósitos: Drivers da inovação tecnológica e da competitividade industrial”. To the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020); national funding by FCT, P.I., through the institutional scientific employment program-contract for R. Calhelha, C. Pereira, and L. Barros contracts. This work has also been supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (451-03-9/2021-14/ 200007).
