Milk lipase and off‐flavour development

The origins of milk lipases and free fatty acids are discussed, together with properties of the principal enzyme responsible for lipolysis in raw milk. Variations in milk free fairy acid levels are shown to result from the net effect of several factors which influence overall enzyme activity and the nature of the fat globule surface. Possible forms of damaged fat are described with evidence suggesting that gross damage such as clumping or coalescence does not necessari 1.v give rise to high free fatty acid values. The risks of lipolysis both with types of milking installation and during the handling. storage and processing of milk are assessed. Levels of free fatty acids likely lo produce detectable rancid flavour are given with typical values for milk and cream in the UK