Effects of Processing Conditions on Lipolysis in Milk

Lipolysis, as measured by acid degree value, was observed in processed milk samples. Temperature of pasteurization was a key factor in control of lipase activity. Minimum legal pasteurization was not adequate to prevent lipolysis completely in samples stored for 7 days at 5°C. However, in most cases heating to 76.7°C for 16s did prevent lipolysis from reaching sensory threshold. Varying the holding times from 16 to 24s did not affect lipolysis when temperature was 74.4°C or higher. Varying homogenization pressures from 105 to 211 kg/cm2 did not alter lipolysis significantly. Differences were noted between eight herd milks for extent of prepasteurization lipolysis and thermal inactivation of lipases in these samples.