Cereal Chem 53:214 - 221.  |  VIEW ARTICLE
Evaluation of Two Infrared Instruments for Determining Protein Content of Hard Red Winter Wheat.

C. A. Watson, D. Carville, E. Dikeman, G. Daigger, and G. D. Booth. Copyright 1976 by the American Association of Cereal Chemists, Inc. 

Two Grain Quality Analyzer (GQA), Model 1, and one Grain Analysis Computer (GAC), Model GAC-2, were evaluated for determination of protein content in hard red winter wheat. The instruments are based on infrared spectrophotometry and each has interference filters, Photosensors, and a computer for analyzing the data. Method of grinding samples affected the results. The grinders sold with the instruments were unsatisfactory, so the Udy Cyclone Mill of the Weber Pulverizer was used. Moisture affected the results only slightly. Variance between duplicate readings on the same sample was small. Correlation coefficients between protein content determined on the instruments and by the Kjeldahl method were highly significant (0.98 to 0.99). The GQA had some electronic problems but was easier to operate and calibrate than the GAC.