Ultrafiltration of Whole Milk: Impact of Homogenization and Ultrafiltration Temperature on Processing Efficiency and Component Retention

The objective of this study was to investigate the impact of thermal and homogenization pre-treatments on ultrafiltration (UF) efficiency and component retention in whole milk (WM). Four milk treatments were examined using a benchtop Optisep filtration system: skim milk (SM) processed in UF at 15 °C, homogenized WM processed in UF at 15 °C (T1), non-homogenized WM processed in UF at 15 °C (T2), and non-homogenized WM processed at 43 °C (T3). UF was performed using 10 kDa membranes to achieve 3× concentration, and the retention and flux rates were compared across treatments. Compositional changes were analyzed at each stage: initial, retentate (2X, 3X, Final), and permeate. The permeate flux varied across treatments; SM showed the highest initial permeate flux and achieved the target concentration in a shorter time. T1 maintained a steady permeate flux over time. T2 exhibited a steep decline in flux, reaching only a 2.5× concentration. In contrast, T3 initially displayed a higher permeate flux due to heat treatment and reduced viscosity. There were significant differences in compositional parameters. T1 retentate had significantly (<i>p</i> < 0.05) higher crude protein (CP), Ca, Mg, and Zn retention. Higher total solids (TS), non-protein nitrogen (NPN), and non-casein nitrogen (NCN), K, and P content were found in T3 permeate. The results from this study demonstrate that homogenization and heat treatment significantly impact the UF performance of WM, offering valuable approaches for achieving dairy product composition.