Orotic acid: a milk constituent - Enzymatic determination by means of a new microcalorimetric method

The presence of orotic acid (a precursor of nucleic acid) in milk is very i mportant in order to ensure its nutritional value and good conservation. In the literature, chromatographic, spectrophotometric and polarographic meth ods are: reviewed. The reported values have a very wide interval range (19- 664 mg l(-1)) and a low precision. The new method proposed in this article employs an enzymatic reaction. It has been improved on standards and then t ested on milk samples. The same samples were also tested by means of a know n spectrophotometric method. The new analytical method for orotic acid dete rmination is reliable; the results are more accurate and more precise if co mpared with the usual methods, and it shows the same sensibility. The calor imetric analysis is faster and easier, owing to the fact that no sample tre atments are required. (C) 2000 Elsevier Science B.V. All rights reserved.