Modification of milk and whey surface properties by enzymatic hydrolysis of milk phospholipids.

Phospholipase A1 were shown to improve foaming properties of skim milk and whey, implying that phospholipases can be useful tools for modifying the functionality of dairy products and ingredients. The ability of three fungal phospholipases and porcine pancreatic phospholipase A2 to hydrolyze milk phospholipids was investigated by using sodium deoxycholate-solubilized milk phospholipid and whole milk. The enzyme with the highest activity in milk was Fusarium venenatum phospholipase A1. Milk and whey were subsequently characterized using tensiometry and interfacial shear rheology. The lysophospholipids released from the fat globule membrane decreased the surface tension of skim milk and whey. A dramatic decrease in the surface shear viscous and elastic moduli indicated a shift from a protein-dominated to a surfactant-dominated interface. The surface shear moduli did not correlate with the foam stability, which was improved by phospholipase A1.