PARTIAL DEACIDIFICATION AND DEMINERALIZATION OF COTTAGE CHEESE WHEY BY NANOFILTRATION

Nanofiltration (NF) membrane processing was investigated as a method f or deacidifying and demineralizing cottage cheese whey (CCW) as a func tion of pH 3.0 to 6.5 so that it could be used in ice cream and other frozen dairy desserts. Membrane flux values after 30 min processing ra nged from 7.5 to 9.0 Lm(-2)hr(-1). Total processing time to produce vo lume concentration ratio 3 (VCR3) retentate and diafiltration against 3 volumes of water to produce DNF3 retentate ranged from 87 to 93 min at pH 3-4.35 to 180 to 210 min at pH 5.5-6.5. DNF3 retentate contained 0.33% lactic acid, 0.65% ash, 11.55% lactose and 14.47% total solids. Membrane rejection of lactic acid ranged from 31% for VCR3 retentate to 67.2% for DNF3 retentate. Membrane rejection of minerals for VCR3 a nd DNF3 retentates was 30% and 71%, respectively.