Free amino nitrogen (FAN) is an important measure prior to alcoholic fermentation as amino acids are required for yeast proliferation and consequently for alcoholic fermentation. Furthermore, FAN is an indicator of beer quality.
A well-established cuvette-based assay measures the FAN content with ninhydrin. Free aminogroups of amino acids react with ninhydrin to form amino-ninhydrin, a chromophore that absorbs light at 570 nm.
Using the SPECTROstar® Nano absorbance reader, FAN content of beer was determined in a cuvette. To allow higher sample numbers, the assay was miniaturized and performed in microplate format. In contrast to the cuvette-based assay, the microplate FAN assay does not require predilution of the sample.
The SPECTROstar® Nano proves valuable in the miniaturization of colorimetric assays as it measures both: cuvettes and microplates.