Comparison of nanofiltration and high pressure ultrafiltration of Cottage cheese whey and whey permeate.

摘要

A DDS LAB-20 unit was used for ultrafiltration (UF) or nanofiltration (NF) of Cottage cheese whey and whey permeate at 3 transmembrane pressures (10, 20 and 30 bars) at constant temperature, flow rate and osmotic pressure. The flux rate increased significantly with pressure increase for NF, while it remained pressure-independent during high-pressure UF (HPUF). The increased pressure resulted in substantial augmentation of the TS rejection by UF and NF membranes, ranging from 39.73 (±0.06) to 67.52%(±1.87) during whey UF and 87.45 (±0.36) to 96.16% (±0.17%) during whey NF with the pressure increase from 10 to 30 bars. The presence of the secondary protein layer at HPUF of acid whey resulted in a significant effect, causing higher TS retention. Therejection of the positively charged multivalent ions (Ca and Mg) was directly proportional to the pressure increase during whey UF. Retention of monovalent positive ions (Na and K) was affected only marginally. P retention was the highest during whey UFtrials, and its permeability increased 3-fold in the absence of whey proteins. During whey NF, the retention of all minerals increased significantly with increase of transmembrane pressure. Without the whey proteins present, all minerals experienced substantially higher retention at high-pressure NF.