In Fig. 9, the development in the total peak area of pH 4.6 soluble
peptides during storage is shown. The peak area of Milk72 devel-
oped in a sigmoidal way and appeared to almost inversely mirror
the hydrolysis of S1-casein 9P and -casein A1
(Fig. 8). After a 2e3
week lag phase, the peak area increased rapidly and levelled out
after the onset of gelation. This is in line with the almost complete
hydrolysis of S1-casein 9P and -casein A1
after 11 weeks, showing
that no more material soluble at pH 4.6 was formed. The total peak
area of Milk95 increased only slightly during the storage period,
confirming that no significant proteolysis occurred.
activity measurement. The decreased rate of proteolysis was most
likely due to a limited accessibility of remaining substrate for PL in
the gel matrix and depletion of preferred cleavage sites.