*3.5. Alkaline Phosphatase Activity*

The activity of Alkaline Phosphatase (ALP), an indigenous milk enzyme with technological importance in respect to the heat treatment of milk, was significantly reduced about 50–59% in bovine and ovine MF permeates (Table 4). This was because the γ-type of ALP is mostly found on the milk fat globule membrane [34] and, thus, its activity followed the partition of the milk fat after microfiltration. The ALP activity of permeate bovine was found to be as high as 407 μg phenol/mL, and it was similar to the value 445 μg phenol/mL reported for bovine skim milk, i.e., 0.05% fat [35]. The same researchers have reported the ALP of ovine skim milk as 4382 μg phenol/mL.


**Table 4.** Effect of microfiltration on alkaline phosphatase (ALP) activity (μg phenol/mL) and protease activities (area <sup>×</sup> 10<sup>6</sup> of peaks of RP-HPLC) in the whey fraction of partially defatted bovine (B) or ovine (O) milk, bovine permeate (BP), bovine retentate (BR) (mean ± SD, n = 3), ovine permeate (OP)

For the same milk, means with different superscript in the same row differ significantly (*p* < 0.05).
