[An attempt to investigate the effect of magnesium ion supplements on changes in levels of nitrates and nitrites in selected pickled vegetables]. / Próba zbadania wplywu dodatku jonów magnezowych na zmiany poziomu azotanów w wybranych kiszokach warzywnych.

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.

[An attempt to investigate the effect of magnesium ions and vitamin C on activity of nitrate reductase of white headed cabbage]. / Próba zbadania jonów magnezowych i witaminy C na aktywnosc reduktazy azotanowej kapusty glowiastej bialej.

The aim of this study was to investigate the effect of magnesium ions and vitamin C on changes in the activity of nitrate reductase of white headed cabbage. During storage of cabbage the activity of nitrate reductase was investigated by the Jaworski method, the level of magnesium by complexometronic method and the level of vitamin C by the Pijanowski method. In addition, the effect of a supplement of magnesium and vitamin C on some changes in the activity of the enzyme was tested. For this purpose, to the incubation mixture, containing the material under study, magnesium ions in the form of magnesium chloride or vitamin C were added in respective quantities. It was found that the nitrate reductase activity as well as the level of magnesium and vitamin C are decreasing towards the inside layers of headed cabbage. Statistical evaluation of the results indicates a high by significant correlation between factors under study. A supplement of magnesium ions or vitamin C to the investigated cabbage significantly increases the activity of the enzyme.

[Changes in nitrate levels and nitrates in carrot roots during storage in an earthen clamp]. / Zmiany zawartosci azotanów i azotynów w korzeniach marchwii podczas przechowywania w kopcu ziemnym.

The aim of this study was the determine the nitrate and nitrite contents in edible parts of 5 varieties of carrot, before clamping and after uncovering, in fresh carrot and dry matter. The colorimetric methods of Griess with modified by Romminger and Straus were used. Dry matter was determined with a drier. Statistical significance of differences in the levels of the studied compounds was calculated by a two-ways analysis of variance. In the studied carrot before clamping average 406.6 mg KNO3/kg and 4.1 mg NaNO2/kg of fresh product was found. These amounts considerably admissible values. After 6-month storage a statistically significant decrease in nitrate levels of Karlena, Perfekcja and Amager was found, in dry matter, whereas a statistically significant increase in Koral variety, while no statistically significant difference in the nitrate level did not changes, was found in Bercoro variety. As concerns nitrites a statistically significant decrease was stated in all carrot varieties.

[Effect of the fermentation process on levels of nitrates and nitrites in selected vegetables]. / Wplyw procesu fermentacji na zmiane poziomu azotanów i azotynów w wybranych warzywach.

The aim of this study was to follow the changes in the levels of nitrates and nitrites throughout the process of fermentation of sauerkraut from white and red cabbage and red beets. The nitrate and nitrite levels were determined in raw and fermentation as well as in red beets and "beet acid" after a week of souring. Nitrate were determined by the brucine method, while nitrates by the Griess colorimetric method. Mean reduction of nitrates in sauerkraut (in relation to raw cabbage) was ca. 55.5% and that of nitrites ca. 76.7%. In the red sour cabbage a decrease in the level of nitrates in relation to the product by ca. 84.1% and in that of nitrites by ca. 67.4% was found. The stabilization of both nitrate levels in both kinds of cabbages followed as after the second month of storage, as confirmed by statistical analysis of the results. In the red beets after the process of fermentation a decrease in the level of nitrates by ca. 91.6% was noted. An undefined portion of the studied compounds passed into the liquid. The "beet acid" contained 595.9 mg/dm1 of nitrates and 3.26 mg/dm3 of nitrites.