3.4.3. Changes in peptide profiles during storage
The development in the peptide profile of Milk72 (Fig. 8)
showed a rapid increase of peaks with 31e34 min retention time
between 0 and 4 weeks storage. These peaks were identified as
proteose peptones. After 8 weeks storage, more peptides appeared
between 17 and 30 min. Most of the peptides eluted late in the RP-
UHPLC, which has been reported previously to correlate with PL
activity (Datta & Deeth, 2003). The peptide profile changed slightly
between 12 and 14 weeks storage, although the total peak area of
the peptide profile of Milk72 remained constant in the same time
period. The most profound change in the peptide profile between
12 and 14 weeks storage was seen in the proteose peptone peaks.
The proteose peptone -casein A1
f(1e105) eluting at 33.0 min
decreased and -casein A1
f(29e105) eluting at 32.7 min increased
(peptides are indicated by arrows in Fig. 8). This shows that PL was
still active after gelation of Milk72, as already suggested by the PL