The determination of lactic acid in milk
Article first published online: 1 MAY 2006
Copyright © 1951 John Wiley & Sons, Ltd
Journal of the Science of Food and Agriculture
Volume 2, Issue 6, pages 279–288, June 1951
How to Cite
Ling, E. R. (1951), The determination of lactic acid in milk. J. Sci. Food Agric., 2: 279–288. doi: 10.1002/jsfa.2740020608
- Issue published online: 1 MAY 2006
- Article first published online: 1 MAY 2006
- Manuscript Received: 3 JAN 1951
A rapid method for the determination of lactic acid in milk is described.
After precipitation with NaOH-ZnSO4 in the presence of BaCl2, the filtrate is treated with FeCl3-HCl reagent, and the colour is measured by one of the three common methods. Reference to standard curves prepared from similar observations on lactic-treated fresh mixed milk enables lactic acid to be determined with an accuracy which compares favourably with the p-hydroxydiphenyl method.
The approximate lactic content may be determined by adding to the filtrate a mixture of ferric chloride, potassium ferrocyanide and salicylic acid solutions.
Although the apparent lactic content of fresh mixed milk is 0.003%, advanced lactation may cause considerable increases in this value.