The natural phenolic compounds have received increasing interest in the last years due to their role in plants. The aim of this study was to determine the influence of microelements (selenium, copper and zinc) on content of phenolic compounds in rye malt. To obtain rye malt, grains were soaked in water with addition of three mineral salts -sodium selenate (Na2SeO4), copper sulphate (CuSO4 5H2O) and zinc sulphate (ZnSO4 7H2O) at different concentrations of salts. Total and individual phenolic compounds in rye malt were determined by spectrophotometric and HPLC methods. It was identified 19 phenol-type compounds, of which 14 were phenolic acids (7 benzoic acid, 6 cinnamic acid and 1 phenylacetic acid derivatives), four flavonoids, and one catechin. Results showed that the majority of determined phenolic compounds were in amount less than 0.1 mg 100 g -1 DM and only four of them (α-resorcylic acid, protocatechuic acid, catechin and kaempferol) were higher content than 1 mg 100 g -1 DM. Individual and total phenolic content in rye malt was higher than in non-germinated rye grain. Protocatechuic acid and catechin were not observed in rye samples, but they were present in all malt samples, indicating formation of mentioned substances in germination process.

Barley is a major world crop ranked as the fourth most important cereal in terms of plant area. Barley is consumed around the world, mostly in the malted form in brewing industry. Recently, many investigations in malt production intensification with biologically active compounds or ferment preparations have been accomplished. However, comprehensive studies on the effect of copper additives on barley grain sprouting are still required. The aim of this study was to explore the influence of different copper concentrations on barley grain sprouting and on the content of total phenols. Barley grains of 92 % viability were soaked in different solutions (Cu 2+ concentration 10-500 mg/l) for 12 hours, left for sprouting at a temperature of 18 ± 2 °C for 5 days, and then dried in the oven for 48 hours at 50 °C. The control sample of grain was soaked in deionized water. The sprouting activity of the grain was determined after sprouting, whereas the content of total phenols was determined after the grain had dried out. The obtained results show that at the copper concentration of 10-50 mg/l, barley grain sprouting activity increases essentially. At the copper concentration of 100 mg/l, barley grain sprouting decreases sharply; moreover, at the copper concentration of 500 mg/l no barley grain sprouting activity was detected. The highest content of total phenols was observed when copper concentration in the solution was 50 mg/l.

Ar promocijas darbu un kopsavilkumu var iepazīties LLU Fundamentālajā bibliotēkā Lielā ielā 2, Jelgavā, LV 3001 un http://llufb.llu.lv. Atsauksmes sūtīt Pārtikas zinātnes nozares promocijas padomes sekretārei LLU Pārtikas Tehnoloģijas fakultātes asoc. prof., Dr.sc.ing. I. Beitānei

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.