Lipolytic Activity During Storage of Human Milk: Stability of the Bile Salt-Stimulated Lipase

Abstract

Bile salt-stimulated lipase activity was monitored in fresh human milk and skim milk during refrigerated (4degreeC) and frozen (-20degreeC) storage, and in the lyophilized milks stored at -20degreeC and at room temperature. Following a sharp initial drop to approximately 77% of the original lipase activity, lipase was relatively stable in frozen or freeze-dried milks during 180 d of storage at -20degreeC. Activity losses were greatest (P < .05) in freeze-dried whole milks and skim milks stored at room temperature, approximating a 30% loss during 30 d of storage. Lipase activity was stable during refrigerated (4degreeC) storage of whole milk for 1 week.