Assimilation of Selenium, Copper, and Zinc in Rye Malt

Trace elements selenium, copper, and zinc are essential minerals for the human body. One of the means to increase the micronutrient content in diets is to add them to food raw materials, for example, to enrich grain with micronutrients during malt production. To obtain rye malt, 3 kg grain was soaked in 10 l water with addition of three mineral salts — sodium selenate (Na₂SeO₄), copper sulphate (CuSO₄ 5H₂O), and zinc sulphate (ZnSO₄ 7H₂O) at different concentrations and different combination of salts. The concentration of selenium, copper, and zinc was determined in rye malt. The obtained results were used to calculate the degree of assimilation of trace elements in rye malt. The interaction of trace elements selenium/copper and copper/zinc was studied. The total amount of selenium, copper, and zinc was analysed by inductively coupled plasma mass spectrometry (ICP-MS). Sample preparation for elemental analysis was performed by wet acid digestion in a closed microwave mineralisation system. The selenium assimilation degree in rye malt was within 10.6 to 12.2%. Accordingly, copper assimilation was 32.8 to 38.0% and zinc 49.3 to 57.0%. Simultaneous presence of selenium/copper and copper/zinc during rye grain soaking promoted the assimilation of each mineral, compared with only one mineral additive.