SOLIDS EXTRACTION OF COD FRAME AND EFFECTS ON ULTRAFILTRATION OF THE AQUEOUS EXTRACT

Grinding, pH adjustment, heat treatment and centrifugation were studie d to recover solids from ground cod frames and to apply ultrafiltratio n (UF) to the resulting aqueous phase. Early heat treatment (90 degree s C/20 min) dissolved collagen into aqueous phase resulting in a very low UF flux. A pH adjustment to 4.5 after grinding (approximate to 0.3 2 cm die), with no heat resulted in efficient separation after centrif uging. UF of the aqueous phase showed an increase in initial flux (23 L/hr m(2)). However, when the same aqueous material was heated and the n centrifuged (1-2% solids removed), UF flux was further increased to 46 L/hr m(2) and this process gave highest solids recovery (90%).