Application of hollow fiber membranes for producing an ultrafiltration permeate from colostrum whey enriched in bioactive compounds

Abstract

Bovine colostrum whey, despite being a source of bioactive peptides and prebiotic oligosaccharides with dietary and nutraceutical applications, presents significant processing challenges due to its high viscosity, making hollow fiber membranes, with their superior ability to control membrane fouling, well-suited for handling such fluids. The objective of this work was to determine optimal ultrafiltration conditions of a 10 kDa hollow fiber membrane to increase efficiency (i.e., permeate flux), selectively retain whey proteins, and facilitate the permeation of peptides (< 10,000 Da) and oligosaccharides (∼600 Da) from bovine colostrum whey. The impact of feed flow rate (3, 6, 9 L min^-1) and transmembrane pressure (1, 2, 3 bar) were evaluated on permeate flux, protein retention, and non-protein nitrogen permeation. Higher permeate fluxes were observed at higher feed flows and moderate transmembrane pressure, demonstrating the ability of turbulence to disrupt the concentration polarization layer at the membrane surface and decrease fouling, as exhibited in the resistance analyses. Higher feed flow significantly increased the cumulative permeate flux during colostrum whey concentration (64.6 $\pm$ 0.1 L h^-1m^-2 at 9 L min^-1 vs. 12.5 $\pm$ 5.9 L h^-1m^-2 at 3 L min^-1, at continuous diafiltration mode and 2 bar), with continuous diafiltration experiments yielding similar permeate fluxes to the ones achieved in discontinuous mode. Processing scale at 12.7 L (2 bar, 9 L min^-1, and continuous diafiltration) enabled 97% protein retention and 95% peptide and oligosaccharide permeation, producing a permeate with 1.3 g L^-1 peptide and 0.42 g L^-1 oligosaccharide. The results of this study highlight the impact of key ultrafiltration conditions of bovine colostrum whey using a hollow fiber membrane for the effective recovery of peptides and oligosaccharides for subsequent evaluation of their biological properties and commercial applications.