Raw skim milk was selectively concentrated at 60 C by ultrafiltration and diafiltration procedures in an Abcor UF-22S unit equipped with high flux membranes. The thermal effect on flux rate, microbiological quality of the retentate and whey protein denaturation were observed under this processing condition. The higher processing temperature increased flux rate, improved microbiological quality and expanded the possibility of denaturing whey proteins, particularly with diafiltration. Composition of the product was normal and alkaline phosphatase negative.
1Universal Foods Corporation, Technical Center, 6143 N. 60th Street, Milwaukee, WI 53218.