Study On Extraction And Identification Of Carotenoids From Natural Egg And Its Stability

Carotenoids are one of antioxidants. Consumption of carotenoids-rich food can remove free radicals. The study showed that intake of adequate carotenoids from a diet may reduce the risk of heart disease, cancer and other chronic diseases. Hen's egg, one of the best sources of nutrition, contains a range of vitamine, mineral and high biological protein. With the exception of breast milk, it is the best one to people. Eggs, according to different feeding methods, can be divided into two kinds:feed-eggs and natural-eggs, hen can produce eggs with big dark-colored vitelline. Because of high concentration of carotenoids and vitamin B2 in vitelline, such eggs are increasingly popular among people.The purpose of this study is analyzed the nutrition component of hen's egg, especially the carotenoids mainly components and its function. It is important to develop the natural egg product. The main results were as follows:1. Nutrition components of natural eggCompare to the components of the yolk from natural egg and the yolk from feed egg, and the results showed that they have their own characteristics. The proportion of the albumen in natural eggs is lower than feed eggs 5.82%, and the proportion of the yolk is higher than feed eggs 5.91%. The proportion of the concentration of water in natural eggs is lower than feed eggs 3.55%, the proportion of the protein is higher than feed eggs 0.07%. The proportion of the fat is higher than feed eggs 0.03%. The concentration of water, crude protein, cholesterin and calcium in natural egg's yolk is lower than in feed egg's yolk, while the phosphorus, crude fat is higher.The value of RCF in feed eggs yolk is 4.0 and the natural is 9.2. The carotenoid in natural egg is significantly higher than in feed egg.2. Extraction of carotenoids from natural eggThe extracting parameters of carotenoids from natural eggs were studied with the method of single factor experiment and orthogonal experiments. The results showed that the optimal extracting conditions were at the room temperature,3 times,75min per times using light petroleum:acetone=2:1 as a extracting solvent, and the 5 times (v/w) of solvent.3. Stability of carotenoids from natural eggThe effects of temperature, illumination, organic solvent, pH and metallic ion on the stability of carotenoid from natural eggs were studied. The results showed that the temperature has no effects at the 80℃in 6 hours. The solvent also has no effects on carotenoid. The carotenoid is stability in alkaline pH while unstabiliy in acidity. Fe2+ has a obvious effects on the stability of carotenoid, and the following is Pb2+. Ca2+,Mg2+,Na+,Al3+,Cu+ also have a certain effects, but not significant. The species of food additive has a significant effects on it while the concentration has little e, glucose can enhance the stability, while acid substance has a variable influence. Oxidant and reductant have an obvious effect on the stability of carotenoids. The stability is generally greatly reduced as the concentration of H2O2 and sodium hyposulfite increase.4. Isolation and identification of carotenoids from natural eggThin-Layer Chromatograqhy (TLC), chemical staining and high performance liquid chromatography techniques were used to identify the species of carotenoids in natural eggs. The results showed the extract contains lutein,α-carotene andβ-carotene.