Natural copaiba oil as antibacterial agent for bio-based active packaging

• The natural copaiba oil was incorporated in paper sheets and poly(lactic acid) films through simple procedures.
• The best results were found with oil content around 20 wt%.
• New biodegradable materials were developed with potential for bio-packaging applications, aiming to increase food shelf life.

This study investigates the antibacterial properties of the natural oil from Copaifera multijuga which was embedded in bio-based materials, to be used in active packaging applications. For this purpose, the naturally extracted copaiba oil was first characterized by gas chromatography and thermogravimetry. Its antibacterial properties were evaluated and confirmed against gram-positive bacteria (Bacillus subtilis). The copaiba oil was incorporated into two bio-based materials: (i) paper and (ii) poly(lactic acid), PLA, films. This incorporation was made following two strategies: either at the surface, thanks to a coating process, or in the bulk, through impregnation (paper samples) or by film casting (PLA films). The antibacterial tests confirmed activity against B. subtilis in paper with a copaiba oil content of approximately 20 wt%. For the PLA films, the same amount showed satisfactory results against the same bacteria. To the best of our knowledge, it is the first time that copaiba oil has been incorporated on paper sheets and plastic films, with the confirmation of the maintenance of the effective antibacterial properties. The materials developed in this work through simple procedures have great perspective to be used as biodegradable packaging with bactericide effect, to improve the shelf life of food products.