Fluorine-Free Superhydrophobic Coating Keeps Eggs Fresher at Room Temperature

Eggs lose moisture, quality and microbial safety quickly when stored at room temperature, but a newly developed coating may slow that decline. Researchers report a water-based, fluorine-free superhydrophobic coating made from TiO2@SiO2 particles and chitosan that reduced weight loss and microbial contamination in eggs kept for 49 days at 25 ± 1 °C.

Instead, TiO2@SiO2 particles act as inorganic structural modifiers, building the rough surface texture needed for water repellency without any fluorine-containing additives.

The water-repellent performance was measured on coated glass. A pure chitosan coating showed a static water contact angle of 82.2°. Adding the TiO2@SiO2 particles pushed that figure to 163.8° for an ethanol-based formulation (EtOH-CS/TiO2@SiO2) and 171.5° for a water-based formulation (H2O-CS/TiO2@SiO2).

Storage trials put the coating to the test over 49 days at 25 ± 1 °C. Eggs treated with the H2O-CS/TiO2@SiO2 coating lost approximately 8.2% of their weight, compared with approximately 10.8% for untreated control eggs.

Coated eggs maintained a Haugh unit of approximately 50.8 at day 49. The coating also delayed changes in albumen pH and yolk index during storage, two additional indicators of egg freshness.

Microbial counts were lower on coated eggs as well. At day 49, the eggshell total viable count in the H2O-CS/TiO2@SiO2 group was 157.6 ± 17.3 CFU per egg, and the yolk total viable count was 241.1 ± 25.6 CFU per egg, indicating reduced microbial contamination relative to the untreated comparison reported in the study.

Titanium content in the edible portion was also assessed. The total Ti content in eggs treated with the H2O-CS/TiO2@SiO2 coating was 0.94 ± 0.07 mg/kg, compared with 0.83 ± 0.08 mg/kg in untreated control eggs.

Overall, the study concludes that the fluorine-free, water-based TiO2@SiO2/chitosan coating reduced weight loss and microbial contamination and helped maintain internal egg quality during the tested 49-day room-temperature storage period. The findings are limited to the conditions and duration tested, and the work is published as an open-access research article in Discover Food.

Subject of Research: A fluorine-free superhydrophobic TiO2@SiO2/chitosan coating for egg preservation at room temperature

Article Title: A water-based, fluorine-free superhydrophobic coating composed of TiO2@SiO2 and chitosan improves egg preservation at room temperature

Article References: Feng, Z., Wang, B., Liang, X., & Chen, S. (2026). A water-based, fluorine-free superhydrophobic coating composed of TiO2@SiO2 and chitosan improves egg preservation at room temperature. Discover Food. https://doi.org/10.1007/s44187-026-01317-w

Image Credits: AI Generated

DOI: 10.1007/s44187-026-01317-w

Keywords: egg preservation, superhydrophobic coating, chitosan, TiO2@SiO2, fluorine-free, food science, room-temperature storage, Haugh unit, microbial contamination, water contact angle, water-based, superhydrophobic