Low Temperature Lactose Hydrolysis of Concentrated Whey Permeates

Abstract
Whey permeates containing 5, 15, and 25% lactose were hydrolyzed at 4°C with /J-D-galactosidase. The 15 and 25% lactose permeates were partly demineralized. Approximately 75 to 90% lactose hydrolysis occurred in 48 h at 4°C and 60 to 70% in 24 h at 4°C. Lowest hydrolysis was with 25% lactose permeates. Demineralization attained at 220 ohm- cm compared with 160 ohm-cm coincided with decreased lactace activity; but enzyme reactivation occurred when po- tassium + ions were added to adjust pH to 6.8.
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