Effect of Nanobubbles on Ultrafiltration Membrane Performance and Properties of Model Cheese Whey

Fouling has been a major concern in membrane processing, requiring frequent cleaning, increasing the time of processing, and reducing the lifespan of membranes. As a strategy to improve membrane filtration processes, our study investigates the impact of nanobubbles (NBs) on the whey ultrafiltration (UF) process and provides insights into the resulting changes in permeation flux, concentration factor, composition, particle charge and size, viscosity, and protein secondary structures. NBs led to significantly enhanced permeation flux up to 60 min (p < 0.05), leading to a higher concentration factor with time, as indicated at 120 min compared to the control. There was a significant increase in protein and total solids concentrations (33 ± 10% and 28 ± 5%) in the final retentate at 120 min for NB-treated cheese whey (NBW) as compared to the control (p < 0.05). While particle size is relatively unchanged with and without NB treatment, increased viscosity in NBW is caused by the increased concentration factors achieved with higher flux for the NBW by the end of UF. FTIR and SDS-PAGE reveal no significant alterations in whey protein secondary structures and fractions, respectively. Overall, membrane efficiency was enhanced by significantly increasing peak flux and concentration factor (34 ± 5% and 40 ± 4%) for NBW compared to CW. Our study presents an innovative approach to reach the targeted total solids/protein for cheese whey concentration in significantly less processing time (28.27% ± 2.33 reduction), with potential energy savings. Therefore, nanobubble technology shows promising potential to improve membrane filtration in the dairy industry with higher permeation flux, reduced fouling, and improved membrane processing efficiency.