Fabrication, characterization, and bioactivity assessment of chitosan microemulsion containing lauric acid-vitamin E against foodborne pathogens

The stable food-grade lauric acid emulsions were developed. • Emulsions showed homogeneous structure and good viscoelastic stability. • The emulsions exhibited notable antioxidant activity and activity against S. aureus . • Antibacterial activity linked to membrane damage and energy disruption. Lauric acid (LA) is an antimicrobial medium-chain fatty acid, but its poor aqueous solubility limits its application in food matrices. To address this, ultrasound-assisted emulsion was developed using LA in vitamin E (VE) oil and chitosan-polyvinyl alcohol (CS-PVA) aqueous matrix. The emulsion exhibited uniformly dispersed oil droplets forming a compact network structure, along with superior stability and viscoelastic properties. No phase separation was observed during storage except for the 5 CP/VL system after 30 days, where CP/VL refers to the CS-PVA/VE-LA. Functionally, the emulsion disrupted bacterial membrane integrity and interfered with cellular energy metabolism. The 10 CP/VL formulation achieved a favorable balance between stability and bioactivity, with DPPH scavenging rate of 26.57% and 2.8 log CFU/mL reduction of Staphylococcus aureus after 2 h at 1% concentration. Overall, this study provides a feasible strategy for enhancing the dispersion and function of LA in aqueous systems for food-related applications. Download: Download high-res image (399KB) Download: Download full-size image