Study On The Separation, Purification And Function Properties Of Lutein From Egg Yolk

Eggs have high quality protein, fat, mineral ,vitamin and other human body essential nutrients. The main egg consumption pattern in our country is the fresh egg. The egg deep processing is inferior to the developed countries. Researchers of Europe, America and Japan have deeply studied poultry egg, separating useful trace ingredients from egg which used as nurture and health products, and gained considerable profit. In this study, we separated lutein from egg yolk. Lutein can effectively reduce the risks of age-related macular degeneration(AMD).By filtering blue light and quenching free radicals,lutein protects eyes. The extraction processing of lutein from egg yolk was optimized. Besides,a simple method for isolation and purification of lutein from egg yolk was developed. The stabilities of the pigment were conduct. To testify its function ,the scavenging free radical activities were evaluated. All the studies provide the basic theory for the general utilization of lutein. The results were shown as follows:First of all, the extractability of 10 organic solvents(benzene, dichloroform, chloroform, cyclohexane, petroleum ether, acetone, tetrahydrofuran(THF), ethanol,ethyl ether, methanol) were compared by the wavelength scanning .The extractability of the better organic solven are tetrahydrofuran and ethanol and that of the worst organic solve is cyclohexane. Furthermore, when THF was added to ethanol, the OD452nm value of the extract increased rapidly. Taking the factors of the temperature, organic agent and ratio of material and solvent for combined experiment, the best extraction processing was as follows: EtOH-THF(2:1) as solvernt, temperature at 30℃, ratio at 1:20 can improve the extraction processing.Based on characteristics of system of egg yolk and unique chemical structure of lutein, we design the process of lutein isolated from egg yolk. By HPLC analysis of the purified lutein, the purity was 73.9%.The lutein from egg yolk was stable to preservatives, temperature not more than 100℃and some metal ions, neutral and basic condition. The lutein is sensitive to sunlight and high temperature(>100℃).The results of lutein scavenging activity of·OH and O2·, indicated that the purified lutein could quench·OH and O2·. Its effect is better than that ofβ-carotene. In the lipid self–oxidation experiment, the purified lutein showed a strong antioxdation at low concentration(<0.2%).Furthermore, lutein and VC had synergetic effects In the experiment of protective effect of lutein against light injury of retina and lens, fat oxidation in the retina and lens of mouse eye could be inhibited by lutein and the activity of T-SOD could be protected by lutein..In general, lutein from egg yolk was natural carotenoids. Extracting lutein from egg yolk, especially isolation and purification of lutein, provide a new way for developing lutein products.