SEQUENTIAL IMPLEMENTATION OF ISOELECTRIC PRECIPITATION FOLLOWED BY ULTRAFILTRATION FOR PRODUCTION OF SUNFLOWER PROTEIN ISOLATES

Abstract

The aim of this study was to improve the yield of protein isolates obtained from sunflower oil cakes by means ofsequential implementation of isoelectric precipitation and ultrafiltration. The proteins were extracted from sunflower oil cake in mild acidic conditions (pH = 6 with solution of NaCl with concentration of 0.5, 1 and 2M). The first fraction of protein isolate was obtained by means of isoelectric precipitation at pH = 4, 3.5 and 3. Total protein, ash and dry matter contents, and residual chlorides of raw material and precipitates were determined. The second fraction was obtained from supernatant taken from the highest yield precipitate by means of ultrafiltration. The ultrafiltration experiments were conducted with an UF10-PAN membrane at a transmembrane pressure of 0.2, 0.35 and 0.5 MPa, and a volume reduction ratio (VRR) of 2, 3, 4, and 5. Total protein, ash, and dry matter contents ofretentates and permeate were determined.