Process for coproduction of crude immunoglobulin y and high-density lipoproteins from hen egg yolk

High value-added products from hen egg are receiving increasing attention from both egg academic and industrial circles due to their potential applications in research and medicine as well as the benefits they bring to egg-breaking industries. This paper reports a simple method for the preparation of immunoglobulin Y (IgY) and high-density lipoproteins (HDL) from hen egg yolk. A water dilution method coupled with (NH4)2SO4 precipitation was employed to prepare the two target proteins. SDS-PAGE under reducing or nonreducing conditions and liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS) were used to characterize the two products. Western blotting and histobiochemical staining were utilized to qualitatively analyze IgY and HDL, respectively. The purities of prepared IgY and HDL were detected by ELISA and a direct high-density lipoprotein-cholesterol assay, respectively. Results show that dilution times 15 makes IgY and HDL separate well from each other. Western blotting proves IgY has an immunocompetence similar to that of human IgG. Histobiochemical staining shows HDL is composed of sugar, lipid, and protein. The quantitative evaluation of the products indicates that approximately 3 kg of IgY and 2 kg of HDL with purities of 72.7 and 71.9%, respectively, are available from 1 ton of shell eggs via this process.