The object of research reported in this paper is grain and leguminous crops of Kazakhstan. Grains and leguminous crops, as well as products that are made from them, are of great importance in human nutrition because they are sources of protein, fat, carbohydrates, some vitamins, and macro and microelements. They contain plant fibers, as well as a number of biologically active substances necessary for the normal functioning of the entire human body. At the same time, modern technologies for processing and manufacturing products from cereals are associated with significant losses of nutrients embedded in them by nature when producing refined products. The problem that needs to be solved is to study the impact exerted on grain crops by various processing techniques and to propose the most optimal ones that make it possible to maximally preserve the nutrients of grain raw materials laid down by nature. A comparative study of the following grain processing techniques was carried out: micronization, extrusion, germination, and fine grinding. Processing modes have been proposed, which could significantly reduce the loss of useful substances of the grain. The chemical and vitamin composition of processed products has been studied. It was established that fine grinding and extrusion processing are the most acceptable because they allowed the use of grain without separating the shells containing the main nutrients of the grain. The suggested processing modes contribute to the production of grain bases and additives with the most optimal vitamin-mineral formulation. This study's results contributed to a better understanding of the impact of the examined techniques for processing grains and legumes on the vitamin-mineral complex of the resulting products. Grain processing modes can be recommended for practical application.