A Method to Measure Pyruvate in Milk

Abstract

A simple procedure to measure pyruvate in fluid milk products was developed. A supernatant fluid from test milk was prepared by clotting with rennet followed by centrifugation. The supernatant fluid was then boiled centrifuged again, and finally membrane-filtered. This filtrate was then used in the spectrophotometric assay of pyruvate via the NADH NAD+ mediated conversion of pyruvate to lactate by lactate dehydrogenase (LDH). This procedure recovered nearly 100% of pyruvate added to various milks, and detected a difference of 1 ppm of pyruvate (p < 0.01).