Nanofiltration (NF)


Membrane filtering systems are frequently used in the industry. In many applications, it has replaced more traditional centrifugal separation, evaporation and coagulation to provide significant benefits in terms of efficiency, product quality and sustainability.

Nanofiltration is a membrane separation method whose molecular weight limit is between ultrafiltration and reverse osmosis. It is used to remove bacteria, viruses, organic residues and hardness. The separation takes place on a selectively permeable layer consisting of an organic semipermeable membrane.

The nanofiltration process offers some advantages over other methods. While it provides both concentration increase and partial demineralization, water and energy usage is very low and easy to maintain since it is a small system.

The nanofiltration process is more successful in fractionation because it has smaller pores than ultrafiltration and microfiltration. Whey powder is added to many foods as a supplement. These food types are meat products, biscuits, ice cream, crackers, chocolate, etc. however, the list can be extended further. The mineral concentration contained in the product during its use in foods may cause undesired taste or structure. Due to the loss of quality it causes, demineralization processes are applied.

The Place and Importance of Nanofiltration Technique in Dairy Industry

Nanofiltration technology is a technology generally applicable in the food industry in many steps of the dairy industry and its typical applications are;

  • Concentration of food, dairy products and beverages or by-products,
  • Pre-concentration of milk in cheese production
  • Salt removal from dairy products or by-products
  • Partial desalination of whey (salt separation process) and preliminary concentration
  • Lactose production and lactose demineralization from whey- Lactose-free milk production
  • Separation of carbohydrates (usually lactose) and proteins
  • Purification of chemicals in the “Clean in Place = CIP” system used in dairy enterprises
  • In food products, it can be listed as reducing and removing color substances.

Demineralization for whey products is a process that increases the nutritional value of the product. The processes previously applied in whey processing are firstly concentrating whey by evaporator, then demineralization by electro dialysis mechanism. Another important advantage of nanofiltration process in milk and dairy applications is that it provides high permeability (NaCl, KCl), while it has low permeability for organic compounds (lactose, protein). The nanofiltration technique reduces both costs and has the advantage of simultaneous concentration-demineralization compared to the Evaporation-Electro dialysis combined system.