Recovery Whey Soy Protein By Microfiltration And Development Of Whey Powder

Soybean whey is one kind of by-products in the production of soy protein isolate. China's annual soybean whey wastewater emissions reach 3 million tons. A good number of functional protein such as trypsin inhibitor, soybean agglutinin, cytochrome C andβ- Amylase, which rich in soybean whey, discard directly to lake and sea, make a waste of resources, furthermore, whey wastewater, with high value of COD and BOD, cause a serious environmental pollution.The paper study on pretreatment of the soybean whey, get the reaults of centrifugal (6000g, 10min, 4℃) and 0.45μm membrane suit for pretreatment of the soybean whey,which not only remove insoluble impurities, but also minimize the loss of the protein. After pretreatment, detect quantity of main components in the soybean whey. The core research of this paper is using soybean whey as raw materials, using of membrane separation technology to recover WSP. In the process of membrane election, broke the traditional choice of ultrofiltraion membrane base molecular weight of the protein, this paper test the particles intensity of whey soy protein by the nano-detector, and analysis protein appearance by scanning electron microscopy. By detecting,get the reaults of that whey soy protein in the solution has a particle average of 285nm, particle size range of 230nm~300nm, mainly distribute at 260nm and 300nm. Most of whey soy protein molecules are gathered together, only very small part are in the form of separate entity. Base of the two test results, select the aperture between70nm and 90nm of the microfiltration-level ceramic membrane as a rejection membrane to recovery and concentrate WSP. Under 25℃,0.3Mpa,the membrane get a high flux between 63L/m2?h~93L/m2?h, and get a protein concentration of more than 90%. The running time of this ceramic membrane system can up to 200min.After washing the membrane at the end of each experiment, the membrane flux has a good recovery.Compared to UF systems, the whole process easier to achieve industrialization. The concentration of WSP is dried by spray drying, protein solubility and decentralized index as two detection target to confirm proper spray drying condition. The paper identified the proper inset temperature is 160℃, and spray pressure is 1.8×105pa to the 40% of the WSP liquid. The products have a good quality with a protein solubility, Especially between pH4~7, the solubility is more than 90%. WSP have a good emulsion indicator between pH of 5 to 7, a good temperature range between 50℃~ 70℃, a good concentration range 2% ~ 5%.