Routine spectrophotometric determination of citric acid in milk powders

Abstract

A modified method for the determination of citric acid based on the chromophore formed between pyridine, acetic anhydride and citrate is described. The technique facilitates the simple, rapid and routine determination of citric acid in milk powder products. The recovery and precision (C.V.) are 95.2 and 2.3%, respectively, and comparison with a specific enzyme assay shows a mean difference between the two methods of 1.5%. The method may also be applied to liquid milks and whey.