Study On Preparation Of Immuno-activated Soybean Peptide Using Membrane Seperation

Soybean peptide has many special processing properties, nutritional properties and physiological functionalities and has a wide use in food industry. This paper studies the clarification of soybean peptide, the processing of ultrafiltration separation of soybean peptide and enrichment of the immuno-activated soybean peptide, and the desalination with nanofiltration membrane of soybean peptide. It offers a method for the industrialized production of immuno-activated soybean peptide.The yield of protein, TCA solubility, turbidity of soybean peptide after clarification was observed to comparative two ways: ultrafiltration and plate filtration. It was shown that they both could clarify soybean peptide. The soybean peptide after these two ways clarification were almost the same in TCA solubility, turbidity, and the yield of protein of soybean peptide after ultrafiltration was higher than that after plate filtration.In the ultrafiltration experiment, how those major ultrafiltrtion-system parameters: pressure, temperature, concentration and pH affecting the membrane flux, how MWCO, materials and pH affecting the molecular weight distributing and basic peptide content, and the effects of soybean peptide treated by fore-and-aft ultrafiltration on immune functions of mice in vitro was studied. It was shown that the ultrafiltration membrane with 8000 MWCO (Molecular Weight Cutoff) should run 180min for a cycle at 0.55MPa, 40℃and pH7.0; when the ultrafiltration membrane with 5000 MWCO should run 180min for a cycle at 0.55MPa, 40℃and pH4.0. all of the peptides could enhance immune function in mice; ultrafiltration treatment on peptide can improve the immune function of peptide effectively and the peptide which was treated by MWCO 5000 under pH4.0 has the highest activity.In the nanofiltration experiment, the nitrogen and chlorine content was observed. It was shown that thenanofiltration membrane with 150 MWCO can be used in the desalting of soybean peptide. The total desalting ratio was 81.46% and the nitrogen content was condensed from 5g/L to 24.57g/L after the discontinuous batch diafiltration. It was indicated that nanofiltration can be used effectively in desalting of soybean peptide and meet the need of industrial production.