As a confirmation the spoilage effect of the P. panacis peptidase,
UHT milk was supplemented with 1, 10 and 100 pkat mL1 and
heated at UHT conditions (see Section 3.4.2). These samples were
stored at 20 C and the pH 4.6-soluble peptides were investigated
after four weeks. During the storage time the concentration of pH
4.6-soluble peptides increased from 2.74 ± 0.05 mM to
6.96 ± 0.12 mM, 15.9 ± 0.3 mM and 27.7 ± 0.2 mM in case of
1 pkat mL1
, 10 pkat mL1 and 100 pkat mL1 added enzyme. These
increases of free peptides are equivalent to the unheated peptidase
containing milk samples. This fact is a further evidence for the heat-
resistance of the peptidase against UHT treatments.