Waste whey from cheesemaking could offer a way to reduce power use during milk powder processing.
A team from the University of Melbourne and the UK’s University of Surrey have demonstrated the salty byproduct helps pre-concentrate milk, making evaporation more efficient and reducing energy use by up to 20%.
Their pilot-scale study showed that whey attracted water out of milk through a semi-permeable membrane in a process called forward osmosis. The exchange required no pumping and the pre-concentrated milk also requires less evaporation and drying.
The plant, located in the UK, used the whey-based ‘draw solution’ to concentrate skim milk by a factor of two and a half. The plant extracted one tonne of water from skim milk using less than 10 kWh – halving the typical energy use.
Forward osmosis, which operates at below 50°C, could potentially be used as an alternative to traditional thermal treatment systems to remove water from other liquid foods such as fruit juices, avoiding the degradation of heat-sensitive compounds and the loss of their bioactive properties.
University of Melbourne researchers involved in the study were Dr George Chen, Professor Sandra Kentish and Professor Sally Gras. Lead researcher Dr Chen said: “For the Australian dairy industry, implementation of this technology could potentially lead to savings of millions of dollars from the reduced steam requirements in thermal evaporators.”
This work has been financially supported through a Victoria Fellowship awarded by the Victorian Government and by The ARC Dairy Innovation Hub supported under The Australian Research Council’s Industrial Transformation Research Program (ITRP) funding scheme (IH20100005). The ARC Dairy Innovation Hub is a collaboration between The University of Melbourne, The University of Queensland and Dairy Innovation Australia Ltd.