Preparation of Low-Lactose Milk Powder by Coupling Membrane Technology

Due to lactose intolerance, there is a growing need for lactose-free or low-lactose dairy products. Herein, a combination of three membrane technologies (UF, electrodialysis (ED), and nanofiltration (NF)) was used as a novel green technology to replace the enzymatic preparation of low-lactose milk powder in the traditional industry. In which, large molecules such as proteins and fats are first retained using UF, mineral salt was intercepted and re-added into milk by electrodialysis, and finally, lactose is recovered by NF. Finally, low-lactose milk powder with a lactose content of less than 0.2% was obtained; meanwhile, the high purity (95.7%) of lactose powder could be effectively reclaimed from the NF concentrate (lactose concentrate). The whole membrane process is based on the physical pore size screening mechanism, without adding any chemical reagents with minimal impact on the physical and chemical properties of milk. These results indicate that process development and optimization coupling of three membrane technologies is very promising in preparing low-lactose milk powder and recovering lactose.