Preparation And Application Of Hen Eggshell Membrane And Its Sialic Acid

This study was untaken to determine the optimum analytical method of calcium andmagnesium in hen eggshell by flame atomic absorption spectrometry (FAAS) withmicrowave assisted digestion. Samples of eggshell were powdered using a blender andstored at4℃until analyzed. A0.25g of sample was accurately weighted for determinationand digested with8ml HNO3–HClO4(7:1v/v) in microwave digestion system. Thedisturbance of samples’ substrate could be avoided after the samples were diluted to1:50with distilled water. In order to remove disturbance of phosphate, sulphate and silicate onthe determination of calcium and magnesium, a releasing agent lanthanum chloride (LaCl3)can be used.3ml0.123mol/L LaCl3was added to each sample. For the determination ofcalcium, the used wavelength was422.63nm, and the current of hollow cathode lamp(HLC) was3.6mA. For the determination of magnesium, the used wavelength was285.20nm, and the current of HLC was6.0mA. The height of burner and the flow rate ofacetylene were7mm and1.5L/min, respectively, for the determination of both calciumand magnesium. The recovery was98%-104%, the relative standard deviations for asample were0.464%and0.294%for calcium and magnesium with P<0.05.Hen eggshell isa significant resource of organic calcium and magnesium in food processing. In conclusion,calcium and magnesium in hen eggshell can be efficiently determined by FAAS withmicrowave assisted digestion.Separation process was selected to make membrane powder between eggshell andmembrane. Indirect pointer was calcium and direct pointer was yield of membrane powder.Four factors were investigated, solid-liquid ratio, rotate speed, stirring time and time of rest.The best test conditions were solid-liquid ratio170-180mL/g, rotate speed310-320r/min,stirring time19-20min and time of rest3.5min. The yield of EM powder was85.00%onthis condition. This procedure was steady and efficient and experimental results wereconsistent with the model prediction.The best way to detect SA was established by spectrophotometry using hydroxyphenoland ninhydrin as colour-developing agent. Regression equation were Y=0.0017X+0.0016,R=0.9993; Y=0.0039X+0.0239,R=0.9996. Ninhydrin was selected indetecting SA because of its better stability and recovery (93.22-95.14%).The732strong acid cation exchange resin was selected in purification of SA andsolvating out crystallization in deep purification. The method of activation and regeneration gumresin was established. The concentration of sample was20ug/mL anddrips was180-270mL. The yield of SA is64.37%and56.24%after the volume of ethylacetate twice ethanol. The method should to be further improved.Optimal technology of sialic acid from hen eggshell membrane was established. Theorthogonal rotation test on the basis of single factor test was selected. The optimalprocedure was selected by investigating temperature, time, ph value and liquid to materialratio. The effect of factors were temperature, time, ph value and liquid to material ratio.The optimal procedure were temperature83℃, time2.1h, ph value1.4and liquid tomaterial ratio101mL/g. The yield of sialic acid was85.00%on this condition. Thisprocedure was steady and efficient and Experimental results were consistent with themodel prediction.