CHARACTERIZATION OF FLUX AND COMPOSITION DURING ULTRAFILTRATION AND DIAFILTRATION OF CHEDDAR CHEESE WHEY

Ultrafiltration (UF) and diafiltration (DF) of cheddar cheese whey hav e been carried out after adjusting pH of whey to various levels rangin g from 3.0 to 7.2 and imparting different heat treatments in a pilot s cale hollow fibre UF plant, possessing PM 50 polysulphone membrane. Co ncentration has been carried out at 50 degrees C and 1.75 and 0.5 bar inlet and outlet pressures, respectively toe volume reduction of 95% f ollowed by diafiltration in order to elicit their effect on flux and c omposition of resultant whey protein concentrate (WPC). It is evident from the results that a significantly higher flux could be obtained wh en whey was processed either at a pH of 3.0 or 7.2 along with a prehea t treatment of 80 degrees C/15 s compared to other levels of pH 4.5, 5 .6 and 6.4 and heat treatment 60 degrees C/30 min. By UF the protein c ontent on dry matter increased to a level ranging from 61.48 to 63.82% from an initial value of 14.89%. The lactose content decreased to a l evel ranging from 25.60 to 28.50% from an initial value of 76.14%. Whe reas the ash content to a level of 3.17 to 6.23% from 8.20%. The pH of processing had significant effect on ash content being minimum at pH 3.0 (3.17%) and maximum at pH 7.2 (6.30%). The calcium and the phospho rus content of retentate followed the similar pattern as that of ash.