Since ancient times, grain has been used for human consumption and feeding of animals. In post-harvest cereal technology, it is important to process and store the grain well, in order to maintain quality until use. In the process of grain processing, the most important is hydrothermal processing. When processing grain for human consumption and animal nutrition, a hydrothermal steaming process is used, the so-called "cooking", which is a technological process of grain treatment with the aim of gelatinizing starch, i.e., to improve the nutritional properties and better digestibility of grain. This research presents the results of changes in the nutritional properties of wheat grains of two cultivars, Kraljica and Srpanjka, and on two cultivars of triticale, Goran and Ranko. The thermal treatment by convection drying was performed at (50°C, 60°C and 70°C), as well as the cooking process in a period of 10 and 15 minutes at a pressure of 0.5 bar. In the drying process, the Srpanjka variety released water faster than other investigated samples at all temperatures. From all the obtained results, it can be concluded that the hydrothermal treatment leads to a change in the nutritional properties of wheat and triticale, or to a change in the content of ash, fat and starch in the grain.