A modified titrimetric method for measuring the activity of wheat germ lipase

Abstract

Wheat germ lipase is a cereal lipase which plays an important role in the growth and storage of wheat products. The commonly used titrimetry is not reliable and accurate enough to determine lipase activity due to its difficulties in identifying the end point when used to measure the alkaline lipase of low activity. In this paper, acidic titration method was utilised, with triacetin as substrate to measure the activity of wheat germ lipase by an automatic potentiometric titrator. The optimum catalysis time is 4 h, the pH value of end point is 6.0, and the initial pH of substrate is 7.7. Under optimum test conditions, the activity of wheat germ lipase was found to be 50.398±0.848 U/mg, within a linear range of 1.0-10.0 mg, and with relative standard deviation equal to 1.682%. This method has proved to be precise and reproducible for measuring alkaline lipase of low activity in aqueous solution.