Variety of dairy ultrafiltration permeates and their purification in lactose production

Abstract

A large amount of crystalline lactose is produced globally. The major source for lactose production is the ultrafiltration permeate of sweet whey. However, some other rich in lactose sources are available in the dairy industry such as ultrafiltration permeates of milk or acid whey. Although lactose remains the most abundant component in all ultrafiltration permeates, their composition can differ considerably. Specifically, large variations in the content of lactate, citrate, phosphate, and calcium are observed. Modern technology of lactose purification is optimized for the processing of feed with low acidity. Lactic acid cannot be sufficiently removed from acid whey ultrafiltration permeate, i.e. the latter is poorly processable with current techniques. However, a toolbox of industrial purification methods offers alternative ways to refine dairy fluids with high lactic acid or calcium content such as acid whey ultrafiltration permeate. Here we discuss the variety of processes that yield ultrafiltration permeates and present a proximate composition of permeates obtained from different sources in the dairy industry. The methods suitable for the purification of ultrafiltration permeate solutions within the framework of lactose manufacture are reviewed in the paper. We also share our vision on how lactose production can be adapted to the processing of ultrafiltration permeates with high lactic acid content