The Specificity of Milk Lipase. I. Determination of the Lipolytic Activity in Milk toward Milk Fat and Simpler Esters

Abstract

A study of the optimum conditions for the activity of milk toward different esters was made. This will provide the basis for the assay methods used in further specificity studies. The reactions were carried out with constant shaking. Under those conditions, appreciable hydrolysis of milk fat occurred with nonhomogenized cream. The emulsion was more stable, however, with homogenized creams. Cream homogenized at 2,500 p.s.i. was therefore used for the milk fat hydrolysis. The pH optima for the milk fat, Tween-20, and methyl butyrate hydrolyses were 8.8–9.1, 8.8, and 8.0, respectively. The pH optimum of 8.7–8.9 for the tributyrinase activity of milk was confirmed. © 1956, American Dairy Science Association. All rights reserved.