Active Proteins and Phospholipids Prepared from Chicken Egg Yolk by Green and Efficient Sequential Separation Technology

In order to achieve the full utilization of the functional components of egg yolk, a green solvent was used to separate bioactive immunoglobulin Y(IgY), phosvitin(PV), and phospholipids(PL) from fresh chicken egg yolk efficiently and continuously. Firstly, the water-soluble fraction was separated from the lipoproteins by water dilution(dilution ratio of 1:10), and the supernatant was salted by 35% saturated (NH₄)₂SO₄ and 0.5% NaCl(w/v) and IgY purified by 8% PEG 6000. The PV in the lipid fraction was further purified in NaCl solution(w/v) at pH5.0, 90 ℃. All lipids in egg yolk were extracted using an ethanol/ethyl acetate ratio of 1:2(v/v), and PL in total egg yolk lipid was further purified using ethyl acetate at 0 ℃. After desalting and freeze-drying, the purity of IgY, PV and PL was 97.38%, 78.63% and 85.94%, respectively. The yield of IgY and PV was 6.15 mg/mL egg yolk and 10.15 mg/mL egg yolk, respectively, and the content of PL in lipids accounted for 35.18%. The PL product may be served as a good source of dietetic applications due to its favorable PUFA/SFA ratio(0.70) and comparable lower n-6/n-3 ratio(5.37). These results proved that IgY, PV and PL can be purified in sequence from egg yolk with high purity. Also, this method is very simple, environment friendly and can provide technical support for the comprehensive utilization of egg yolk.