Preliminary Tests on the Concentration of Skim Milk Using a Tangential Flow Filtration System in Laboratory Applications

The purpose of this study was to characterize the Vivaflow® 200 (Sartorius Lab Instruments GmbH & Co.) cross-flow cassette laboratory system for the concentration of up to 2 L of partially skimmed milk (fat content 1.6%, sugars 4.9%, protein 3.2%) The milk, with an initial dry matter content of 10.56%, was processed in triplicate until three volumetric concentration ratios of 3-2.5-2 were obtained—defined as the ratio of the initial volume of milk to the final volume of concentrate—using a peristaltic pump set to 90% of its maximum flow rate, ensuring an average permeate flow rate of 13.89 ± 0.75 L h⁻¹, which varied depending on the concentration ratio achieved. The final pH of the concentrate ranged from 7.16 to 7.12, while the dry matter content achieved was 20.58%, 16.24%, and 14.43%, respectively, for the three concentration ratios. Finally, the data collected made it possible to characterize the laboratory system in terms of the membrane’s hydraulic performance, flow rate (J) over time, and effective concentration factor, expressed as the percentage of dry matter (%) in the concentrate relative to the feed milk. With the aim of developing and optimizing pilot-scale processes the proposed tool, thanks to its ease of use, high throughput, low cost, and high productivity, represents a viable approach for the preparation of milk concentrates and permeates for use in pilot-scale biotechnology processes.