Study On Continuous Extraction Of Natural Active Components From Egg Yolk

Egg yolk contains a variety of natural bioactive substances,which are of high application value.The extraction of bioactive components from egg yolk has become a research hotspot.However,the domestic research on the extraction of bioactive components from egg yolk is at the stage of extracting single active component,which leads to waste of other bioactive components and low added value of eggs.Therefore,it is of great significance to study the continuous extraction technology to separate various bioactive components.In this study,fresh egg yolk was used as raw material,and various extraction methods were used to extract egg yolk immunoglobulin,egg yolk hyperphosphoprotein,egg yolk oil,and lecithin in turn.The method is simple and low in cost,which can increase the added value of eggs and avoid waste of resources.The main contents include the following four aspects.(1)Extract yolk immunoglobulin.The supernatant(water-soluble component)and sediment(yolk particles)rich in yolk immunoglobulin were obtained by water dilution and centrifugation,and then the water-soluble component was salted out by inorganic salt precipitation to obtain yolk immunoglobulin.The four factor and three level orthogonal experiment was used to optimize the process conditions.The results showed that under the conditions of 8 times of dilution,p H 5.0,25 min of centrifugation,and 70% of ammonium sulfate concentration,6.66 mg of yolk immunoglobulin could be extracted from 1 g of egg yolk solution,the recovery rate was 91.33%,the purity was 81.03%,and the protein activity was 77.71%.(2)Extract high phosphoprotein from yolk.The yolk particles separated in the above step are used as raw materials,and the solvent extraction method is used to separate the lipid from the protein to obtain the upper oil(lipid mixture)and the lower sediment(lipoprotein),and the neutral salt precipitation method is used to separate the yolk hyperphosphoprotein from the lipoprotein.The response surface Box Behnken three factor and three level experimental design was used to determine the optimal conditions for preparing egg yolk hyperphosphoprotein: the ratio of mixed organic solvent(95%ethanol: n-hexane V/V)was 1:1.08,the amount of organic solvent was 6.35 times,and the concentration of sodium chloride was 1.75mol/L.Under the optimal conditions,9.99 mg egg yolk hyperphosphoprotein could be extracted from 1g egg yolk solution,the recovery rate was 83%,the purity was 84.15%,and the nitrogen phosphorus ratio was3.72.(3)Extract egg butter.The egg yolk oil in the lipid mixture was extracted by vacuum distillation,and the crude lecithin was separated from the egg yolk oil by acetone insoluble method;The yolk oil in the residue of lipoprotein was collected by solvent extraction.Response surface Box Behnken three factor three level experiment design was used to optimize the extraction conditions.The results showed that the extraction was carried out once with absolute ethanol for 50 minutes;Under the optimum preparation conditions,149.44 mg of egg yolk oil was obtained from 1 g egg yolk liquid extracted with acetone for three times.The recovery rate was 93.27%,and the extraction rate was74.13%.(4)Extract lecithin from egg yolk.The crude lecithin in the above step is used as the raw material,and the ultrasonic assisted absolute ethanol is used to dissolve the crude lecithin,and the refined lecithin is extracted by the compound salt precipitation method.The response surface Box Behnken four factor three level experimental design was used to obtain the optimal conditions for preparing refined lecithin: ultrasonic power 475 W,ultrasonic time 32.00 min,ultrasonic temperature 28.2 ℃,and zinc chloride concentration37.00%.Under these conditions,80.2mg of refined lecithin can be prepared from 1g egg yolk solution,with purity of 76.51%,recovery of 78.57% and extraction rate of 62.36%.