It is known that the feed of hens affects the quality of eggs. The eggs of hens which were fed a fossil shell diet were reported to have higher egg shell strength. We compared the eggs of hens fed coral powder feed (C samples) and the eggs of hens fed standard feed (S samples) in terms of cooking characteristics.

The quality of S samples and C samples, the weight ratio of egg shell, egg white, and yolk, egg shell thickness, and the texture of the boiled eggs were measured. Moreover, the structure was observed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, the raw egg white and yolk were analyzed in terms of their total amino acids using HPLC, and sensory evaluation was performed.

The degree of decreasing Haugh unit for C samples was suppressed. C samples had higher amounts of calcium in the whole egg, the egg shell and membrane than standard samples. Sensory evaluation indicated that the taste preferences for the C samples of boiled yolk were significantly higher than those for the S samples.