Lipase redistribution in cows' milk during induced lipolysis: I. Activation by agitation, temperature change, blood serum and heparin

Abstract

SummaryEffects of agitation, temperature change, blood serum and heparin on lipolysis and on distribution of lipoprotein lipase (LPL) in cold-stored cows' milk were measured. All individual milks (n = 135) were susceptible to activation treatments. With ‘gentle’ treatments, induced lipolysis was strongly correlated to spontaneous lipolysis (r ≥ 0·74). In contrast, induced lipolysis in response to ‘vigorous’ treatments was more variable (0·7 > r > 0·34) and levelled off in milks with high spontaneous lipolysis. Induced lipolysis always resulted from an increase in LPL associated with cream. Strong correlations (0·79 ≤ r ≤ 0middot;94) were found between free fatty acid levels and cream LPL. All treatments (except heparin addition) also promoted lipolysis/unit cream LPL.