Microbial stabilization of craft beer by filtration through silica supports functionalized with essential oil components

Abstract The brewing industry uses conventional pasteurization to assure beer microbial stability, but this process compromises its quality characteristics. This study proposes a novel cold pasteurization technology based on filtration through silica microparticles (5, 10, 25 or 50 μm) functionalized with essential oil components (EOCs). After the synthesis and characterization of the supports, craft beer was filtered through a bed of EOC-functionalized particles to assess their capability to entrap and/or inactivate beer microbiota. The microbiological analysis of filtered beer showed that the supports presented remarkable removal capacity against Escherichia coli, mesophilic bacteria, lactic acid bacteria, and mold and yeast. The preservation potential of the filtration technology remained steady after filtering multiple samples and previous washing with a high water volume. The determination of potential leaching of the immobilized EOCs resulted in zero release of the grafted molecules in the beer samples filtered through the bed of particles. Moreover, differences among control and filtered beers detected by a panel of untrained judges were scarce or nonexistent. The proposed technology can be considered an effective novel mild preservation method for craft beer as it can reduce the microbial load of the product and can prevent negative effects on the sensory properties of beverages.