The changes of secondary structures and properties of lysozyme along with the egg storage.

The changes of lysozyme structure during egg storage were investigated by Fluorescence spectroscopy, Circular Dichroism spectroscopy and Fourier Transform-Raman spectroscopy, and the relationships between lysozyme properties (enzyme activity, emulsibility and foamability) and secondary structure were also discussed. During the storage, the percentages of α-helix and β-turn declined, conversely the β-sheet and random coil increased, the polarity of microenvironment around tryptophan residue gradually decreased. The results suggested that the conformation of lysozyme became more flexible during egg storage. Lysozyme activity was decreased but ESI and FA of lysozyme rose up with the storage duration. Correlation analysis revealed that second structure of lysozyme significantly affected lysozyme properties during egg storage. These findings would certainly be useful for further study of food storage and production.