[An attempt to investigate the effect of magnesium ion supplements on changes in levels of nitrates and nitrites in selected pickled vegetables].

The aim of this study was to examine the effect of magnesium ions on some changes in the nitrate reductase activity in the white headed cabbage as well as a practical application of the results obtained in vegetable souring. As experimental material were used: white and red headed cabbage, red beets and the same vegetable in the soured form. Vegetable souring was performed using a traditional method as well as a modified one, considering a supplement of magnesium chloride at various levels during the process of souring. The activity of nitrate reductase in the white headed cabbage was determined by the Jaworski method. In raw and soured vegetables the level of nitrates was determined by brucine method and that of nitrites by the Griess colorimetric method. A supplement of magnesium ions to the incubation mixture containing raw white cabbage resulted in an increased activity of the studied enzyme by 17.0-34.8% and was significant in all magnesium ions concentrations used. The introduction of adequate amounts of magnesium chloride to soured vegetable production resulted also in a significant decrease in the nitrate and nitrite levels. An organoleptic evaluation of soured vegetables made by a traditional method and by using a supplement high quality, although the smell of white headed cabbage and "beet acid" has slightly however, significantly deteriorated.