Casein hydrolysate was continuously produced by hydrolysis of bovine c
asein with Protease Type XXIII (from Aspergillus oryzae) in a pilot-sc
ale formed-in-place membrane reactor. A high percentage (>99%) of TCA
soluble nitrogen in the hydrolysate (product) was achieved after 45 mi
n at 37 degrees C and pH 7. The product was completely soluble over pH
range 2-9. Water sorption increased 4 to 6.5 times at water activity
of 0.35-0.95 as compared to intact casein. The immunologically active
casein and immunologically active whey protein in the product were red
uced 99% and 97%, respectively. Long term operation showed that the me
mbrane reactor maintained steady production of casein hydrolysate long
er than 17 hr.