An Improved Colorimetric Assay for Bacterial Lipase in Nonfat Dry Milk

A modification of McKellar and Cholette's (1986) colorimetric method for determining lipase activity in reconstituted non-fat dry milk was developed. The method uses the color reaction between Fast Blue BB and the β-naphthol (BN) enzymatically cleaved from β-naphthyl cap-rylate (BNC) as a measure of lipase activity. In the modified method, a solvent system is used to clarify the sample rather than extracting the colored product. This modification allows measurement of total sample lipase by excluding centrifugation. In addition, the modified method has greater sensitivity with equal ease of use.