5. Protein and Moisture

5.1. Near-Infrared Transmittance Analysis Method for Protein and Moisture Content in Whole Grain and White Flour (Infratec 1241)
Whole grain and white flour samples are analyzed using a Foss Infratec 1241 Grain Analyzer. This is a near infrared transmittance (NIT) instrument for simultaneous and accurate determination of protein and moisture in whole grain and white flour samples. NIT-analysis, like all other spectrophotometric measurements, is an indirect method to predict protein and moisture based on the fact that these constituents in grain absorb electromagnetic radiation in the near-infrared region of the spectrum.
Calibrations for the Infratec 1241 were jointly developed by the United States Department of Agriculture (USDA) Grain Inspection, Packers and Stockyards Administration (GIPSA) and Foss Tecator.

5.2. Reference Methods to check calibrations
Protein
The LECO FP-528 combustion method nitrogen analyzer is used as a reference method for protein. The LECO FP-528 nitrogen analyzer combusts flour in an oxygen atmosphere followed by a series of catalytic reactions that result in nitrogen gas. The nitrogen gas is used to determine total protein. Percent crude protein = % nitrogen x 5.70. American Association of Cereal Chemists (AACC) Method 46-30.
Moisture
The reference method for moisture follows AACC Method 44-15A. Moisture content is determined by measuring the loss in weight of a sample when heated under specified conditions.