Cereal Chem 48:276 - 282.  |  VIEW ARTICLE
Rapid Biuret Method for Protein Content in Grains.

R. M. Johnson and C. E. Craney. Copyright 1971 by the American Association of Cereal Chemists, Inc. 

A rapid, simple, and inexpensive method for determining protein content in small grains and corn is proposed. Powdered cupric carbonate is added to the finely ground grain which is then dispersed in a dilute alkali-alcohol solution. The mixture is shaken, filtered, and the absorbance value read at 550 nm. The color intensity of the filtrate is proportional to the protein concentration. Meter readings of 391 samples of various grains representing 3 crop years were correlated with Kjeldahl protein content. Correlation coefficients were highly significant for all grains tested. Total time per sample is about 5 min. when run sequentially. Reagent costs are about 5 cents per sample. With the exception of the special mill, only standard laboratory equipment is used in the test.