ULTRAFILTRATION UF is a type of low pressure membrane filtration that separates colloidal particles into high molecular weight substances, the size of which lies in the range of 1-10 µm, this range includes casein, whey proteins, large fat molecules.
Working pressure, in general, does not exceed 1 MPa. Ultrafiltration membranes are also the basis, the skeleton, the so-called. support which is applied with composite membranes used in other processes such as reverse osmosis, pervaporation and gas separation. Ultrafiltration is used primarily for the clarification of solutions, i.e. removal of large, colloidal particles from them, as well as for thickening protein solutions.
The main application of ultrafiltration is the processing of whey and milk.In the case of whey processing, the ultrafiltration unit allows the concentration of whey proteins (proteins) along with the separation of minerals and lactose. Typically, ultrafiltration plants are used to produce whey protein concentrate (WPC) with a protein content in solids of 34% to 85%.
By using subsequent post-treatment, such as MF microfiltration, it is possible to completely isolate the proteins and obtain whey protein isolate (WPI). Both WPC and WPI have huge demand in Europe, and in some countries WPC and WPI are exchange traded commodities.
When using UF to concentrate milk, a high protein retentate is obtained, with parallel separation of lactose and minerals. The retentate is used to produce various types of cheese and milk protein concentrate (MPC), or, in the case of further protein isolation, milk protein isolate (MPI).
Feta cheese and other cheeses of this type are produced by fully concentrating milk using an ultrafiltration process. Then starter cultures, rennet, salt and other additives are added to the resulting retentate and sent directly to the packaging.
Main Application of Ultrafiltration
Ultrafiltration is used for the processing of whole milk, skimmed milk, fermented milk, whey and for the clarification of fruit juices:
• standardization of the content of milk proteins, casein;
• preliminary thickening of milk proteins for the production of cheese, cottage cheese, cheese, Feta cheese;
• production of WPC whey protein concentrate and WPI isolate;
• clarification of fruit juices.