Research On Separation,Characterization And Stability Of Carotenoids From Changbai Mountain Specialty Eggs

1. The nutritional and functional composition and color of egg yolk from ChangbaiMountain specialty eggs was analyzed including the content of moisture, crude fat, ash,protein, mineral (sodium, potassium, calcium, iron, magnesium, zinc), vitamin A, vitaminE and other nutrients, as well as cholesterol, lecithin and carotenoids and other functionalcomponents. Using RYCF in colorimetric assay, the color of the egg yolk was analyzed.The contents of nutrients and color of egg yolk were compared with those of conventionaleggs and free range eggs. The results showed that the moisture content in the special localeggs was lower, and no significant difference was observe in the crude fat content amongthe three kinds of eggs. However, the contents of ash and protein were higher than those ofthe other two kinds of eggs. Potassium, sodium, calcium, magnesium contents in theChangbai Mountain specialty eggs with the exception of iron and zinc were close toconventional eggs but lower than free range eggs. The special local eggs had the deepestegg yolk color. Changbai Mountain specialty eggs also showed fine quality with highvitamin A, vitamin E, lecithin yet low cholesterol.2. On the basis of results of the single-factor experiments, the carotenoids extractionprocess of the Changbai Mountain specialty eggs was optimized. Comparative analysis ofthe three kinds of extraction technology was done to determine carotenoids rate. Wedetermined the optimal conditions for microwave method as the extraction process of theChangbai Mountain specialty eggs carotenoids, building a microwave extraction of theeggs’ carotenoids quadratic regression model at the same time. Here is the quadraticregression model in the microwave extraction of carotenoids:Y=22.568+1.383X1+0.454X2+0.393X3+0.520X4-0.389X12-0.661X22-0.801X32-0.396X42-0.403X1X2+0.391X1X3(Where: X1is the ratio of liquid to solid, X2for the microwave power/W, X3formicrowave extraction temperature/℃, X4for the microwave extraction time/min). The optimal condition for this equation is that: the liquid to solid ratio23:1, microwave power600W, the microwave extraction temperature of43°C, the microwave extraction time18min. under this condition carotenoids yield value was measured23.991mg/100g, whichis close to the predicted value of24.045mg/100g, proving the model to guide theproduction practice is suitable.3. Such factors as light, heat, pH, oxidant conditions were researched on the stabilityof the Changbai Mountain specialty eggs carotenoids. In conclusion, changbai Mountainspecialty eggs carotenoids were sensitive to light, high temperature and acid, with a certaindegree of oxidation resistance.4. Contrastive analysis of the composition of the Changbai Mountain specialty eggs,farm eggs and ordinary eggs’ carotenoids by thin layer chromatography and highperformance liquid chromatography, showed that Changbai Mountain specialty eggscontain lutein, zeaxanthin and beta-carotene while farm eggs contain lutein and zeaxanthin,lutein containing only for ordinary eggs. The lutein content in Changbai Mountainspecialty eggs is very rich, three times over that of farm eggs’, even four times that ofordinary eggs. Separation and purification of the lutein in crude extracts of carotenoidsfrom Changbai Mountain specialty eggs were conducted with column chromatography of100-200mesh silica gel. We used petroleum ether-acetone system for gradient elution,obtaining the lutein purity of95%.