The purpose of the work reported in this paper was to study and develop the separation and concentration of blood plasma proteins by the application of ultrafiltration (UF) technology. These proteins may be added as functional ingredients to food to emulsify, bind water or fat, form foams or gels, and alter flavor, appearance, and texture. As blood was drawn from chickens, a sodium citrate solution was added to avoid coagulation. Blood was centrifuged at 900g and plasma was obtained and ultrafiltered using a membrane in a single batch plant. Pressure, feed flowrate and cutoff of the membrane were studied using a 2(3) factorial experimental design. The UF concentrate contained 7-12% total solids (TS), with a protein level of 5-11%. A mathematical model of the system's performance in terms of protein concentration variation was developed, which showed that feed flowrate plays an important role in blood plasma concentration. (C) 2002 Elsevier Science Ltd. All rights reserved.