A Photometric Method for Estimating the Lipase Content of Milk

Summary The butyryl, caproyl, and caprylyl esters of 2-naphthol-6-sulfonic acid (sodium salt) have been synthesized and purified. These esters, particularly the butyryl, possess a reasonable degree of water solubility and are all hydrolyzed by some component of raw milk, presumably the lipase. 2-naphthol-6-sulfonic acid (sodium salt), one of the products of hydrolysis of these esters, can be estimated photometrically by using Folin and Ciocalteu's phenol reagent to develop color. A photometric method for estimating the lipase content of whole milk is presented which makes use of these esters as substrates and in which color is developed with the above mentioned reagent.