The Research Of Extracting Protein From Meal With Membrane-separation Technology

The protein is the important material base that the mankind depends on for existence. The rapeseed is the important industrial crops of our country. A large number of rapeseeds leave a large number of rapeseed meals after extracting the oil. The content of the protein is abundant in the rapeseed meal, but there is a large amount of the harmful material or the material of resisting nutrition, thus it will prevent the rapeseed meal from directly utilizing to a great extent. Membrane separation is an advanced single-phase and heterogeneous separating technology that technology has been developed in recent years with many characteristics, such as purity high for separation, simple technique condition, low technique cost and little disposal of pollutants etc. With membrane-separate technology development at full speed of technology, membrane-separate technology enters our country gradually, and widely used in many fields. Especially, as the production scale of oil and output of production are expanded rapidly at present, produce a large number of rapeseed meals, and eager demand an advanced separation technology like membrane-separation to transform downstream technique of traditional oil industry.This paper studies the feasibility that it applies membrane separation technology to extracting protein from rapeseed meals. At the same time, it fixes on the best technical parameters to serve the industrialized production process.In the experiment for extracting protein from rapeseed meal, through two comparable experiments extracting protein from rapeseed meal with alkali solution and salt solution, discuss separately the effect of PH in solution, concentration of salt solution, temperature, ratio of materials and solution and extracting time on extraction rate. The results indicate that salt solution is better than alkali solution for extracting protein from rapeseed meal on the whole. The best technical parameters about the protein extracts among the salt solution show: Temperature 40 ℃; Ratio of materials and solution is 1/15; The density of salt is 5.0%; Time is 40min. The extraction rate of the rapeseed protein is 89.87% under this condition.In the experiment for separating protein with ultra-filtration technology, discuss separately the effect of PH, concentration, temperature, velocity of flow and pressure in solution on volume flow of solution through membrane during ultra-filtrating. Through successive experiment, the results indicate that the significance of the effect among themon volume flow of solution through membrane is successively concentration of solution, pressure (include velocity of flow), temperature and PH of solution. The best parameters: pressure P =0.2Mpa, velocity of flow S =lm/s, the concentration of solution is same as the concentration of solution extracted, temperature T =40, PH =10. At this time the volume flow of solution through membrane reaches 55.2 L/ (m2h ). Through four times ultra-filtration, protein purity is up to 91.1% (with dry materials counting), and does not contain noxious substances , such as sulphur glucoside and plant sour ,etc. ; The protein color of is shallow, lightly taste.The experiment of membrane contamination during the ultra-filtration shows: the volume flow of solution through membrane drop to 20. 6% original after successively ultra-filtrate 10 hours, the volume flow of solution through membrane can recover 89.84% of original through washing with sour and alkali; the rate of cleanout K about membrane contaminative layers reaches 87.2% in membrane face.Initially analysis and fix on the technical flows and technical equipments for the industrialized production process in theory.