In the present study, attempts have been made in optimising the conditions for whey lactose hydrolysis to prepare whey based soups or syrups.β-galactosidase enzyme was extracted from Kluyveromyces marxianus and partially purified. Two different alkali Potassium hydroxide (KOH) and Sodium hydroxide (NaOH) were used to bring the whey to required pH. Then, the whey lactose hydrolysis was carried out at two different temperatures, 25 and 37°C using whey with different pH (6.6 and 7.0). Out of eight combinations of alkali metal ions (K+, Na+), pH (6.6 and 7.0) and temperature (25 and 37°C) used, yielded increased lactose hydrolysis than that of Na+ ions. pH 7.0 was found to be effective in lactose hydrolysis than pH 6.6. Hydrolysis incubation temperature 37°C showed more hydrolysis percentage than 25°C. From the above results, it may be concluded that, pH 7.0, temperature 37°C and alkali metal ion K+ combination yielded the possible highest lactose hydrolysis percentage (86.8).
P. Rajakala and P. Karthigai Selvi , 2006. The Effect of pH, Temperature and Alkali Metal Ions on the Hydrolsis of Whey Lactose Catalysed by β-Galactosidase from Kluyveromyces marxianus. International Journal of Dairy Science, 1: 167-172.