Thymol-phospholipid complex: a promising green natural preservative with improved physicochemical properties and bioactivities

With the growing global demand for safe, green food additives to replace synthetic preservatives, thymol has emerged as a promising candidate owing to its broad-spectrum bioactivities. However, its industrial application is severely hindered by inherent limitations including poor water solubility, high volatility, and environmental instability. Herein, a thymol-phospholipid complex (Thy-PC) was successfully fabricated via optimised anti-solvent precipitation, achieving a complexation efficiency of 81.2 ± 1.3%. Structural characterisation verified that thymol was molecularly dispersed in the phospholipid matrix in an amorphous state, leading to a 2.5-fold improvement in water solubility and a significantly reduced oil-water partition coefficient. Thy-PC exhibited enhanced antioxidant activity (comparable to vitamin C), superior antibacterial efficacy against E. coli and S. aureus, and excellent photostability. Notably, its antioxidant performance in soybean oil matched that of synthetic BHT, providing a practical strategy for developing high-efficiency natural food preservatives.