New Strategy for the Covalent Immobilisation of Phenolic Compounds on Silica Particles to Fight Against Foodborne Pathogens.

The immobilisation of essential oil components (EOCs) on food-grade supports is a promising strategy for preserving liquid foods without the drawbacks of direct EOC addition such as poor solubility, high volatility, and sensory alterations. This study presents a novel method for covalently immobilising EOCs, specifically thymol and carvacrol, on SiO particles (5-15 µm) using the Mannich reaction. This approach simplifies conventional covalent immobilisation techniques by reducing the steps and reagents while maintaining antimicrobial efficacy and preventing compound migration. The antimicrobial effectiveness of the EOC-SiO system, applied as an additive, was tested against foodborne pathogens (, , and ) inoculated into phosphate buffer solution and fresh apple juice. The results showed high antimicrobial activity, with inactivation exceeding 4-log reductions, depending on the EOC type, target microorganism, and medium. Moreover, the addition of functionalised particles did not affect the juice organoleptic properties. This study demonstrates that the Mannich reaction is an effective method for developing antimicrobial systems based on the covalent immobilisation of EOCs on silica particles, and offers a practical solution for food preservation without compromising food quality.