Membrane-Based Fractionation of Milk Proteins for the Production of High Value Dairy Ingredients—A Systematic Review

Membrane-based processes have emerged as efficient alternatives to conventional separation methods because they enable protein fractionation under mild processing conditions while preserving protein functionality and bioactivity. Furthermore, whey, traditionally regarded as a by-product of cheese manufacture, is now recognized as a valuable source of proteins and bioactive compounds that can be recovered and valorized through membrane processing. Despite this, the literature on protein fractionation processes based on membrane technologies remains limited across different membrane technologies and operational scales. This systematic review evaluates microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) in the context of milk protein fractionation, with a focus on industrial relevance, process limitations, and the resulting high-value protein fractions. Unlike previous narrative reviews, the study integrates comparative performance metrics, including pressure, protein recovery, purity, process limitations, and resulting products. Following the PRISMA guidelines for the selection and assessment of eligibility for a systematic review, 55 studies were included in the final qualitative synthesis. The analysis shows that UF consistently achieves high protein recovery (>90%) and represents the dominant industrial technology for the production of whey protein concentrates and isolates, although its efficiency is limited by concentration polarization and flow rate drop at elevated volumetric concentration factors. Consequently, future research should prioritize integrated performance reporting, quantitative measurement, and integration of sustainability indicators to enable more robust industrial application of membrane-based dairy technologies. Moreover, more reporting bases on standardized industrial performance indicators and commercial case studies are needed to support the wider adoption and optimization of membrane technologies in dairy processing.