Physicochemical properties and stability of milk permeate as influenced by ultrafiltration processing parameters

The objective of this study was to determine the effect of membrane molecular weight cut-off (5 and 10 kDa), and filtration temperature (25, 15 and 10 °C) on the physicochemical properties of milk permeate (MP). Although MPs produced had a similar gross chemical composition, MP produced with the 10 kDa membrane at 25 °C had the lowest pH (6.64) and ionic calcium content (2.33 mM), while MP produced with the 5 kDa membrane at 10 °C had the highest levels of 6.82 and 2.85 mM for pH and ionic calcium, respectively. Incubation of MPs at 60 °C resulted in precipitation, with MPs produced with the 10 kDa membrane having larger, less soluble and thermodynamically more stable particles than MPs produced with the 5 kDa membrane. These results demonstrate that filtration parameters significantly affected the physicochemical properties of MPs, with implications for downstream processing.