Measurement of Wet Gluten Content in Wheat Grain and Flour: From the Development of a Measurement Procedure – to the Production of Reference Materials for Calibration of IR Analyzers

The new regulations for maintaining the Federal State Information System „Grain“ have raised the requirements for the timeliness and reliability of data entered on grain quality measurement results. One of the key parameters for grain acceptance and data submission to the FGIS „Grain“ is the wet gluten content, which is determined using approved IR grain analyzers. These IR analyzers require timely calibration. Therefore, the development of new, accessible calibration tools is a pressing issue.The goal of the research described in the article is to develop a measurement procedure and reference materials for the wet gluten content in grain and flour, aiming to reduce the time and cost of calibrating IR analyzers and, ultimately, to improve the accuracy of measurements conducted by these analyzers.To this end, the factors influencing the measurement results were investigated, and the contribution of each influencing factor was evaluated. As a result, a range of approaches has been proposed to enhance measurement accuracy: firstly, the use of distilled water with a regulated temperature for gluten washing; secondly, the replacement of the manual method with a mechanized one, the use of more precise scales, and the employment of a gluten press; thirdly, it is recommended to pre-determine the moisture content of the initial sample of grain (flour) for the subsequent calculation of the sample mass, among other specified conditions. The article presents the characteristics of the measurement procedure FR.1.31.2025.50337, „State System for Ensuring the Uniformity of Measurements (GSI). Procedure for Measuring the Wet Gluten Content in Grain and Flour“, developed by the authors, along with the results of a study of the metrological characteristics of reference materials for wet gluten content in grain and flour, which were certified using this procedure. The application of this procedure will enable the serial production of reference materials for the metrological support of gluten content measurements. The introduction of these reference materials will make calibration tools for IR analyzers accessible to regional metrological centers. Accredited testing laboratories will be able to perform accuracy control independently. Overall, the quality of metrological services for grain processing enterprises will be enhanced.