The effect of adding minerals on fouling from whey protein concentrate - Development of a model fouling fluid for a plate heat exchanger

Deposits formed on the surface of heat treatment equipment in the dairy industry compromise product quality and process efficiency. Whey protein concentrate (WPC) solutions have been used by a number of researchers to investigate the fouling mechanism and to understand cleaning, in an attempt to optimize thermal treatment processes of milk. However, differences in the fouling from milk and WPC have been found at high temperatures, possibly as a result of the mineral content of the two solutions. The effect of adding minerals (calcium and phosphorus) on fouling and cleaning behaviour of WPC has been investigated. Solutions of differing mineral content were tested; deposits formed in each temperature region of the PHE were analysed for chemical compositions. Increasing the mineral content decreased the extent of fouling and altered the deposit composition closer to that of milk. Overall cleaning times and cleaning rates, under standard conditions, were found to be dependant on the deposit composition and cleaning chemical concentration. Alternation of the cleaning chemical with water at different time intervals throughout the cleaning process elucidated the balance between hydraulic (physical) and chemical effects during cleaning.