Influence of salting processes on water and lipid dynamics, physicochemical and microstructure of duck egg

Water and lipid changes play important roles for the quality formation of salted duck eggs. In the present study, low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) were introduced to monitor water and lipid dynamics of duck egg during salting as nondestructive methods. Four proton pools with different mobilities in fresh duck egg matrix were identified by LF-NMR transverse relaxation, and salting significantly changed the proton mobility due to the gelation of egg yolk, release of lipid and watery of egg white. MRI showed high density of proton with lower mobility and higher mobility in egg yolk and white, respectively, and the brighter region of egg yolk in T-1 images continuously decreased from vitelline membrane to center. The variations in the relaxation parameters and MRI images have a close relationship with other quality characteristics of duck eggs induced by salt. Therefore, LF-NMR and MRI could provide information about water and lipid dynamics of duck eggs during salting, and have great potential for quality assurance in salted duck eggs as a fast and non-destructive method.