4.10 - Free Amino Nitrogen of Malt by Spectrophotometry
The determination of the free amino nitrogen content of malt using colorimetry with ninhydrin. The method gives an estimate of amino acids, ammonia and, in addition, the terminal nitrogen groups of peptides and proteins. Proline is partially estimated at the wavelength used. The method is not specific for α-amino nitrogen since γ-amino butyric acid, which is present in malt worts, also gives a colour reaction with ninhydrin.
It is necessary to use EBC Methods 4.5.1 or 4.6.1 and 8.10