Optimising α-Lactalbumin Recovery from Whey via Membrane Filtration: The Role of Transmembrane Pressure Across Membranes Varying in Polymer Type and Pore Size.

There is strong commercial interest in the successful fractionation of whey protein into pure products. However, the effect of environmental conditions on membrane fractionation is not fully understood. In the current study filtration pressures, membranes of various pore sizes and types, and pH manipulation, were employed to investigate the effect of operating conditions on the enrichment of α-lactalbumin from whey protein. All of these factors were shown to affect the protein profile of the filtrate produced. Industrially relevant polyethersulfone microfiltration and ultrafiltration membranes, on a small-scale membrane filtration rig, were both able to filter out lactoferrin and lactoperoxidase, producing a filtrate that primarily contained β-lactoglobulin and α-lactalbumin. When scaled-up to a large cross-flow system, only the microfiltration membrane demonstrated a filtrate fractionation with an α-lactalbumin-enriched protein stream. When operated at 3 bar with a 1 in 3 dilution of a whey protein feedstock, a 140% increase in α-lactalbumin was achieved compared with a commercial whey protein liquid feed. This study shows the importance of the optimisation of all conditions during membrane fractionation and demonstrates that this technique can be used to produce an α-lactalbumin enriched product of industrial relevance. Supplementary Information: The online version contains supplementary material available at 10.1007/s11947-026-04241-0.