Qirong Dong

Thyme oil (TO), an aromatic compound derived from Thymus species, exhibits potent antioxidant and antibacterial properties. To address its defects of high volatility and susceptibility to oxidation, TO was encapsulated in chitosan oligosaccharide (COS)-stabilized oil-in-water emulsions using a two-step emulsification method with ultrasound assistance. The droplet size of TO-in-water emulsions decreased significantly with increasing ultrasound power and treatment time, achieving sizes below 240 nm with an encapsulation efficiency exceeding 90%. The COS interface layer, combined with polyvinyl alcohol (PVA), effectively enhanced emulsion stability by preventing phase separation and maintaining droplet size and zeta potential during storage. Compared to its free form, the encapsulation of TO in the emulsion significantly improved the antioxidant activities, as evidenced by the enhanced ABTS (1.25-fold) and DPPH (1.33-fold) radical scavenging activities, at equivalent concentrations. Additionally, the TO emulsions exhibited superior antibacterial and antifungal properties, with minimum inhibitory concentration (MIC) values reduced by half and effective inhibition of Escherichia coli, Staphylococcus aureus, and Penicillium italicum growth. These findings highlight the potential of TO emulsions as an effective delivery system for improving the functionality and stability of TO in fresh food preservation applications.

Efficient detection and degradation of fungicides are greatly concerned with aquatic food safety. Herein, a multifunction CoFe₂O₄/MoS₂@Au (ACMS) composite was synthesized for crystal violet (CV) and malachite green (MG) photocatalytic degradation and SERS determination. As the construction of the Z-scheme heterostructure of ACMS, which enhanced the light absorption capability and the separation efficiency of photoexcited carrier significantly, ACMS possessed an excellent photocatalytic performance with a degradation rate of 94.76% for CV under simulated solar light irradiation. Furthermore, the multifunction ACMS exhibited superior SERS capability with a detection limit (LOD) of 4.309 × 10⁻² μg L⁻¹ for MG residues in water. And the ACMS substrates could be utilized to determine the MG residues in crucian carp extract, resulting in a recovery rate of 96.00~116.00%. In addition, such multifunction heterojunctions were performed for in situ monitoring of the photodegradation process. This research opened up a novel perspective on the applications of heterojunction-based multifunction materials for food safety control.

For survival and quality of human life, the search for better ways to ensure food safety is constant. However, food contaminants still threaten human health throughout the food chain. In particular, food systems are often polluted with multiple contaminants simultaneously, which can cause synergistic effects and greatly increase food toxicity. Therefore, the establishment of multiple food contaminant detection methods is significant in food safety control. The surface-enhanced Raman scattering (SERS) technique has emerged as a potent candidate for the detection of multicomponents simultaneously. The current review focuses on the SERS-based strategies in multicomponent detection, including the combination of chromatography methods, chemometrics, and microfluidic engineering with the SERS technique. Furthermore, recent applications of SERS in the detection of multiple foodborne bacteria, pesticides, veterinary drugs, food adulterants, mycotoxins and polycyclic aromatic hydrocarbons are summarized. Finally, challenges and future prospects for the SERS-based detection of multiple food contaminants are discussed to provide research orientation for further.