Effects of different copper salts on the physicochemical properties, microstructure and intermolecular interactions...

This study was conducted to investigate the effects of different copper salts on the physicochemical properties, microstructure and intermolecular interactions of preserved egg white (PEW) during pickling. With increased pickling time, the alkalinity of the pickling solution and the moisture of PEW pickled by three copper salts (CuSO₄, CuCl₂ and Cu(CH₃COO)₂) gradually decreased, while the pH showed dynamic trends. During the early stage of pickling, the viscosity of PEW changed dynamically. With the progress of pickling, the hardness and springiness of PEW increased gradually and the α-helix structure gradually transformed into a more stable β-structure. The main forces that maintained PEW gel were ionic and disulfide bonds. In the early stage of pickling, the alkali penetration rate of CuCl₂ pickled preserved eggs was faster, and better gel strength and network structure were observed, followed by CuSO₄ and Cu(CH₃COO)₂, while there were no significant differences in the later stage of pickling.