Effects of CaCl2 on the structure of high-density lipoprotein and low-density lipoprotein isolated from rapidly salted separated egg yolk

Abstract

According to previous research, adding CaCl₂ to the salting solution improves the quality of salted separated egg yolk. To further understand the improvement mechanism of CaCl₂, this paper investigated the effect of CaCl₂ on the structure of high-density lipoprotein (HDL) and low-density lipoprotein (LDL) during the salting process. The results indicated that the addition of CaCl₂ can affect the composition of HDL and LDL apolipoproteins, improving the orderliness of the HDL structure and the looseness of the LDL structure. It was discovered by atomic force microscopy (AFM) that adding CaCl₂ to the salting solution can weaken the aggregation behavior of HDL. Simultaneously, the addition of CaCl₂ decreased the relative content of intermolecular β-sheets in the secondary structure of HDL and LDL, influenced their tertiary conformation, and prevented HDL and LDL from participating in the formation of a three-dimensional gel structure by influencing their hydrogen bonds and hydrophobic interactions.

Keywords: 3D fluorescence spectroscopy; Atomic force microscope; Hen egg yolk; X-ray diffraction.