Enhanced antimicrobial activity of essential oil components immobilized on silica particles

[EN] The antimicrobial activity of essential oils components (EOCs) is well-known. However, their high volatility and powerful aroma limit their application in the formulation of a wide range of food products. In this context, the antimicrobial activity of carvacrol, eugenol, thymol and vanillin grafted onto the surface of three silica supports with different morphologies, textural properties and chemical reactivities (fumed silica, amorphous silica and MCM-41) was evaluated herein. Materials characterization revealed a good immobilization yield and all the devices showed a micro-scale particle size. Sensory evaluation revealed that sensory perception of EOCs decreases after covalent immobilization. Moreover, immobilization greatly enhanced the antimicrobial activity of the essential oil components against Listeria innocua and Escherichia coli compared to free components. The incorporation of EOCs immobilized on silica particles into pasteurized milk inoculated with L. innocua demonstrated their effectiveness not only for in vitro conditions, but also in a real food system.

Authors gratefully acknowledge the financial support from the Ministerio de Economia, Industria y Competitividad and FEDER funds (Projects AGL2015-70235-C2-1-R, AGL2015-70235-C2-2-R and MAT2015-64139-C4-1-R (MINECO/FEDER)) and the Generalitat Valenciana (Project PROMETEOII/2014/047). M.R.R. is grateful to the Ministerio de Education, Cultura y Deporte for her grant (AP2010-4369). The authors also thank the Electron Microscopy Service at the UPV for support.