Ultrafiltration of cheese whey: Achieving high protein rejection and sustaining membrane efficiency

Abstract

The objective of this study is to characterize the ultrafiltration (UF) of cheese whey (CW) by measuring permeate flux variations and observing changes in the water permeability of the membrane throughout the process. We also aimed to analyze the differences between the compositions of CW and the materials generated after UF (ultrafiltration concentrate (UC) and permeate (UP)). UF lasted 66 min, after which a volume concentration factor of 2.54 was reached. Flux decline during UF was caused by concentration polarization, and not by fouling, because cleaning recuperated 94.55% of membrane efficiency. Though lactose was more retained than usual, gel electrophoresis demonstrated the 1.77-fold increase in protein content, depicting stronger bands of β-lactoglobulin and α-lactalbumin in UC. Therefore, UF satisfactorily separated proteins from CW; however, to effectively remove lactose we suggest a previous filtration step with higher molecular weight cutoff to retain larger molecules before using 10 kDa. Novelty impact statement Over 99% of protein rejection was achieved in the UF of cheese whey (CW). Membrane's efficiency was regained to 100% of its capacity after cleaning procedures. Lactose was not efficiently separated from CW when compared to other studies.