QUANTITATIVE determinations of serum and urinary proteins are of considerable clinical importance; that such estimations are made relatively infrequently is probably due to the lack of a simple yet trustworthy technique. The methods of Esbach and Aufrecht are notoriously crude, while the gravimetric and the Kjeldahl methods are too laborious for ordinary clinical purposes. Of the colorimetric p...

The established Kjeldahl technique for estimating nitrogen (King and Wooton, 1956) was employed using a Markham still and standardized sulphuric acid and sodium hydroxide with phenolpthalein as indicator. Urinary nitrogen was estimated on 1 ml aliquots. For faeces and food 10-20 g aliquots of homogenate previously prepared with a Silverson mixer were weighed and digested on the macro scale. The...

J. Inst. Brew. 115(2), 122–127, 2009 In this study we present a ninhydrin based microwell assay that can be utilized in place of the traditional Kjeldahl method for the determination of the protein content of beer or wine. In addition, the assay is ideal for the determination of free amino acids in beer (FAN), a term understood and used by brewers, and yeast assimilable nitrogen (YAN) used by e...