Rape is an important oil crop with a wide range of uses. Harvested rapeseed must be cleaned and dried before processing. The process of drying rapeseed as a small-seeded crop has its own specifics. One of the new drying methods is the use of microwave radiation, the disadvantage of which is uneven heating of the product. The purpose of this work was to study the modes of drying rapeseed by electromagnetic radiation in the ultra-high frequency range in combination with filtration. The indicators of the intensity of oilseed drying by infrared irradiation on the experimental stand were determined. The analysis of the conducted studies showed that the temperature of seeds at the maximum microwave power rises in general 1.5 to 1.8 times faster than at half the power. The higher the seed moisture content is, the higher the rate of temperature increase. After each blowing cycle, which lasted for five seconds, the temperature of the rapeseeds was set higher than the previous temperature, and after increasing the blowing time up to fifteen seconds, the temperature decreased by 8–12°C and cyclically stabilized. The applications of microwave drying represented in the paper are environmentally friendly, since the seeds do not come into direct contact with the products of gas combustion, which deteriorate its quality due to the possible penetration of carcinogenic components into the products. Experimental data was taken into account when developing the design of a small-sized grain dryer for farms, in which the drying process takes place without heating the air as a heat carrier.

Vegetable oils belong to a large group of substances consumed on a daily basis. World vegetable oil production is soaring, reducing the popularity of animal fats. Heavy metals pose a threat to human health. It is estimated that about 80% of the daily dose of heavy metals enters the human body through the consumption of food. Hence, it is necessary to monitor their concentrations in food products. Besides, the presence of heavy metals is thought to have possible negative influence on the quality of oils, especially on their taste and smell. Heavy metals may also accelerate the process of the rancidifiction of oils. Rapeseeds, soybean seeds and linseeds were selected for the analysis because they are one of the most popular oilseeds and at the same time they differ in terms of growing conditions. The analyses of different fractions and the ready-made product were also performed. The aim of the study was to determine the variation in concentrations of heavy metals, iron and manganese in different fractions during production. The significant concentrations of iron, manganese and zinc were observed in oilseeds. It was also shown that during different stages of oil refining the concentrations of metals decrease. The concentrations of metals are compared with those reported in literature.