Polymeric microfiltration of skimmed milk in Edam cheese process II. Effect on the composition and nutritional quality of whey protein concentrate

Microfiltration (MF) using the 800 kDa spiral wound Synder FR polymeric polyvinylidenefluoride (PVDF) membrane was used in the production of concentrated skimmed milk retentate for production of Edam cheese vat milk with elevated protein concentration of 42 g/kg. Concentration factors (CF) of 4 to 70 were used. Skimmed milk was used as reference (protein concentration 34 g/kg). The MF permeate was processed to native whey protein concentrate (NWPC). Whey from cheese process was clarified, concentrated by ultrafiltration and freeze dried to WPC powders. The protein and amino acid composition of WPC powders were significantly affected by CF. The content of some large molecular weight whey proteins increased as a function of concentration factor. In addition, the relative concentration of caseinomacropeptides was increased. Even after considerable diafiltration at CF 70, the content of residual aromatic amino acids in WPC powders was=elevated, indicating presence of significant quantity of true whey proteins. The content of large molecular weight whey proteins was reduced in NWPC. The negative impact of microfiltration on the nutritional value of the WPC powders limits the usability of these ingredients especially in infant nutrition.