The performance evaluation of Eugenol and Linalool microencapsulated by PLA on their activities against pathogenic bacteria

Abstract

The essential oils (EOs) have great potential as a natural alternative to preserve foods against spoilage and poisoning pathogens, and they are healthy and safe. Their incorporation in polymers has been of great interest in active packaging for preserving fresh food. This work aims to evaluate the effect of encapsulation of two different oils (linalool and eugenol) as antimicrobial agent activity against Escherichia coli, Salmonella enterica subsp. enterica serovar Choleraesuis, Staphylococcus aureus, and Listeria monocytogenes. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) evaluated the EOs and their capsules with polylactic acid biopolymer. It was analyzed using the agar disc-diffusion testing method to determine the inhibition zones. The active release curves were constructed to elucidate activity efficiency. The minimum bactericidal concentration (MBC) values on E. coli, Salmonella, S. aureus, and L. monocytogenes were 0.39%, 3.13%, 0.78%, 1.56%, and 0.39%, 12.50%, 0.39%, and 12.50%, for the eugenol and linalool, respectively. To eugenol against E. coli (60 mm) and linalool against Salmonella (32 mm) exhibited relevant inhibition zones results. The EOs released promoted the inhibition zone by the volume of the EOs released over 24 h (2.2 μL/L to eugenol and 1.5 μL/L to linalool). Moreover, UV–vis results determined the active release reporting that the capsules have a prolonged efficiency, continuing to release the active up to 40 days, indicating potential application in active food packaging, extending the shelf life of food.