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THE FRACTIONATION OF THE WORT AND BEER NITROGEN COMPOUNDS BY PRECIPITATION WITH PHOSPHOTUNGSTIC ACID
Author(s) -
Bishop L. R.
Publication year - 1949
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.1949.tb01486.x
Subject(s) - phosphotungstic acid , nitrogen , chemistry , fractionation , precipitation , amino acid , yield (engineering) , composition (language) , absorption (acoustics) , yeast , chromatography , food science , organic chemistry , biochemistry , materials science , physics , meteorology , catalysis , linguistics , philosophy , metallurgy , composite material
In studying the nitrogen compounds of wort and beer, the first requirement is for an understanding of the broad general types of nitrogen compounds in wort and of their approximate proportions. An attempt to provide such a separation has been made by adding phosphotungstic acid to wort in a series of regularly increasing quantities, and separating and analyzing the fractional precipitates. The results indicate precipitation in a series of jumps, with corresponding jumps in the composition of the precipitates. Fully‐built‐up proteins have a very small proportion of free amino nitrogen, whereas simple mono‐amino‐acids yield 100 per cent.; thus the complexity of the precipitates can be assessed from these values. Indications have been obtained of compounds containing approximately 1, 2, 4, 8, 15–16 and around 30 per cent, of free amino nitrogen. In beer the corresponding complex groups have been found in similar amounts with the simpler compounds reduced or absent owing to absorption by yeast. The results obtained have been supported by preparation and analysis of the complex wort nitrogen compounds.