Abstract:This study aims to develop a bio-based，edible，and highly water-resistant coating suitable for biscuits to address the issue of moisture absorption and spoilage after opening. Egg white protein （EWP） was used as the matrix，with the addition of lipophilic beeswax （BW） and the plasticizer glycerol. Ultrasonic treatment was applied to optimize the coating performance. Experimental results showed that under ultrasonic conditions of 200 W and 30 minutes，EWP exhibited improved physicochemical properties，including smaller particle size （80.19 nm），enhanced hydrophobicity，and more ordered structure. When combined with BW，the resulting coating liquid displayed excellent water barrier properties and uniformity，with the lowest water vapor permeability [3.51 g/（m·d·Pa）] observed in the 200 W/10 min treatment group. The coating applied to the biscuit surface significantly extended the shelf life，reduced the weight gain of the biscuits，and maintained high hardness and crispness. In summary，the EWP-BW composite coating enhanced its hydrophobicity of beeswax and improved adhesion via ultrasonic treatment，effectively improves the moisture protection and freshness preservation of biscuits，thereby extending their storage life after opening.