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

Eggs are susceptible to moisture loss, quality deterioration, and microbial contamination during room-temperature storage. In this study, a fluorine-free, water-based TiO 2 @SiO 2 /chitosan composite coating was developed for egg preservation, with TiO 2 @SiO 2 particles used as inorganic structural modifiers to construct a rough interfacial structure without fluorinated low-surface-energy modifiers. The static water contact angle measured on coated glass increased from 82.2° for the pure chitosan coating to 163.8° for the EtOH-CS/TiO 2 @SiO 2 coating and 171.5° for the H 2 O-CS/TiO 2 @SiO 2 coating. During 49 d of storage at 25 ± 1 °C, eggs treated with the H 2 O-CS/TiO 2 @SiO 2 coating showed a weight loss of approximately 8.2%, compared with approximately 10.8% for the untreated Control, and maintained a Haugh unit of approximately 50.8 at 49 d. The coating also delayed changes in albumen pH and yolk index during storage. At 49 d, the eggshell total viable count of the H 2 O-CS/TiO 2 @SiO 2 group was 157.6 ± 17.3 CFU/egg, and the yolk total viable count was 241.1 ± 25.6 CFU/egg. The total Ti content in the edible portion of eggs treated with the H 2 O-CS/TiO 2 @SiO 2 coating was 0.94 ± 0.07 mg/kg, compared with 0.83 ± 0.08 mg/kg in the untreated Control. Overall, the fluorine-free, water-based TiO 2 @SiO 2 /chitosan coating reduced weight loss and microbial contamination and contributed to the maintenance of internal egg quality during the tested 49-day room-temperature storage period.