Ewa Ciska

Changes in the content of health-promoting compounds and antioxidant activity of broccoli after domestic processing.

The effect of water- and steam-cooking on the content of vitamin C, polyphenols, carotenoids, tocopherols and glucosinolates, as well as on the antioxidant activity of broccoli, are reported. Flavonoids, phenolic acids, vitamins C and E, β-carotene, lutein, and glucosinolates in domestically processed broccoli were quantified using high-performance liquid chromatography (HPLC) methods; total polyphenols were determined with Folin–Ciocalteu reagent. The antioxidant capacities of broccoli extracts were evaluated using the Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The results indicated that steam-cooking of broccoli results in an increase in polyphenols, as well as the main glucosinolates and their total content as compared with fresh broccoli, whereas cooking in water has the opposite effect. Steam-cooking of broccoli has no influence on vitamin C, whereas cooking in water significantly lowers its content. Both, water- and steam-cooking of broccoli results in an increase in β-carotene, lutein, and α- and γ-tocopherols as compared with fresh broccoli. Similar effects of steaming and water-cooking of broccoli on their antioxidant activity were observed.

Glucosinolate Derivatives in Stored Fermented Cabbage

The research focused on the glucosinolate (GLS) breakdown products formed during the fermentation of cabbage. A relationship between the contents of degradation products in fermented cabbage and native GLS in raw cabbage was investigated. The effect of fermented cabbage storage on the contents of individual compounds was also assayed. Ascorbigen formed from one of the degradation products of glucobrassicin (indole GLS) was found to be a dominating compound in fermented cabbage. Irrespective of the time of fermented cabbage storage, the content of ascorbigen reached approximately 14 micromol/100 g. Neither the content of isothiocyanates, the major degradation products of aliphatic GLS, nor that of cyanides exceeded 2.5 microM. Storage of cabbage caused periodical increases and decreases in the contents of cyanides and consequent declines in the contents of isothiocyanates. The highest relative contents (expressed as a percentage of the native GLS content) of degradation products--ranging from >70 to 96%--were reported for the products of glucoraphanin degradation, whereas the lowest-- <5% --were reported for the products of sinigrin degradation.

Influence of Fermentation Conditions on Glucosinolates, Ascorbigen, and Ascorbic Acid Content in White Cabbage (Brassica oleracea var. capitata cv. Taler) Cultivated in Different Seasons

The content of glucosinolates (GLS), ascorbigen, and ascorbic acid in white cabbage (Brassica oleracea var. capitata cv. Taler) cultivated in different seasons (summer and winter) was determined, before and after spontaneous and starter-induced fermentation. Different salt concentrations (0.5% NaCl or 1.5% NaCl) were used for sauerkraut production. Glucoiberin, sinigrin, and glucobrassicin were dominating in raw white cabbage cultivated either in winter or summer seasons. Ascorbigen precursor, glucobrassicin, was found higher in cabbage cultivated in winter (2.54 micromol/g dw) than those grown in summer (1.83 micromol/g dw). Cabbage fermented for 7 d was found to contain only traces of some GLS irrespective of the fermentation conditions used. Ascorbigen synthesis occurred during white cabbage fermentation. Brining cabbage at low salt concentration (0.5% NaCl) improved ascorbigen content in sauerkraut after 7 d of fermentation at 25 degrees C. The highest ascorbigen concentration was observed in low-sodium (0.5% NaCl) sauerkraut produced from cabbage cultivated in winter submitted to either natural (109.0 micromol/100 g dw) or starter-induced fermentation (108.3 and 104.6 micromol/100 g dw in cabbages fermented by L. plantarum and L. mesenteroides, respectively). Ascorbic acid content was found higher in cabbage cultivated in summer and fermentation process led to significant reductions. Therefore, the selection of cabbages with high glucobrassicin content and the production of low-sodium sauerkrauts may provide enhanced health benefits towards prevention of chronic diseases.

Effect of Light Conditions on the Contents of Glucosinolates in Germinating Seeds of White Mustard, Red Radish, White Radish, and Rapeseed

The study was aimed at determining the effect of light conditions on contents of glucosinolates (GLS) in germinating seeds of white mustard, red radish, white radish, and rapeseed. The seeds were germinated in light and dark, at 25 degrees C, for up to 7 days. As compared to the nongerminated seeds, in seeds exposed to light and germinated for 4, 5, 6, and 7 days the content of total GLS was observed to decrease by 30 to 70% depending on the species. Germination in conducted the dark for the respective periods of time resulted in decreases of total GLS not exceeding 25%. The changes in the concentration of total GLS were attributed to aliphatic GLS predominating in seeds, yet in the case of white mustard to sinalbin belonging to aralkyl glucosinolates. Although seeds germinated in the dark, as compared to those exposed to light, were characterized by a higher total content of indole GLS, the percentage contribution of that group of compounds in white mustard, red radish, and white radish remained at a similar level, irrespective of germination time. Only in the case of rapeseed was the percentage of the sum of indole GLS observed to increase from 17 to up to 45% once the seeds were exposed to light and to 50% once they were germinated in the dark.

Changes in nutritional value and cytotoxicity of garden cress germinated with different selenium solutions.

The selenium supply in almost all European countries is below the recommended daily intake, and different strategies are followed to fortify foods. In the present work, the influence of germination of garden cress ( Lepidium sativum cv. Ogrodowa) in different selenium solutions (Na(2)SeO(3) and Na(2)SeO(4)) on Se uptake, total antioxidant capacity, glucosinolates, protein, and amino acids was studied. Cytotoxicity in HL-60 human leukemic cell line was also assessed. The addition of selenite (Na(2)SeO(3)) or selenate (Na(2)SeO(4)) led to a significant increment in Se uptake in garden cress sprouts, and the highest Se content was observed at 8 mg/L in both inorganic Se solutions (36-38 microg/g of dm). The Se-enriched sprouts presented a large total antioxidant capacity (142-157 mumol of Trolox/g of dm), total glucosinolate content (99-124 microg/g of dm), protein (36-37% dm), and total essential amino acid content (40-41 g/100 g of protein), and no cytotoxicity on HL-60 human leukemic cells was observed. Garden cress sprouts obtained with selenite solution at 8 mg/L presented the best nutritional qualities and might provide a substantial proportion of Se in European diets. Bearing in mind the high nutritional value of sprouts, these may serve for the production of functional foods.

Broccoli by-products improve the nutraceutical potential of gluten-free mini sponge cakes

This study describes the successful development of new gluten-free (GF) mini sponge cakes fortified with broccoli leaves. The aim of this study was to evaluate the effect of broccoli leaf powder (BLP) on the content of biologically active compounds and the antioxidant capacity of GF mini sponge cakes. Broccoli leaf powder was a good source of nutritional components, including proteins and minerals, as well as bioactive compounds such as glucosinolates and phenolics. Glucosinolate content was higher than expected, which points to a synergistic interaction between bioactive compounds and the food matrix. The incorporation of BLP into GF mini sponge cakes significantly (p<0.05) increased their antioxidant capacity. The overall sensory acceptance of GF mini sponge cakes was affected by increasing BLP content. The addition of 2.5% BLP as a starch substitute resulted in an optimal improvement in the nutraceutical potential of GF cakes without compromising their sensory quality.

Evaluation of Seasonal Variations in the Glucosinolate Content in Leaves and Roots of Four European Horseradish (Armoracia rusticana) Landraces

Abstract In comparison with other cruciferous vegetables, horseradish has rarely been the object of scientific research, and the knowledge about the composition, content and distribution of glucosinolates (GLS) in different organs of horseradish plants is limited. Therefore, the aim of this study was to evaluate changes in the GLS content in leaves and roots of four horseradish landraces during the growing season. The presence of 13 GLS was determined in the examined horseradish tissues, and glucoraphanin, glucoraphenin and napoleiferin were noted for the first time in the species. During the growing season, the content of individual GLS changed significantly. The rate and direction of these changes varied across the examined landraces and plant organs. In the leaves, between May and June, the content of sinigrin, the main GLS in all horseradish landraces, decreased in Bavarian (40%) and Hungarian (11%) horseradish, increased (22%) in Creamy horseradish, whereas in Danish horseradish, the difference was not significant. Despite the changes observed in the first two months, the highest content of sinigrin was noted in July in all horseradish landraces. During the growing season (August-October), the content of sinigrin fluctuated in the roots of Creamy and Danish landraces, reaching the highest level in October and September, respectively, whereas in the roots of Hungarian and Bavarian landraces, sinigrin concentrations continued to increase and peaked in October. Changes in the content of other, minor GLS during the growing season often differed from those noted in sinigrin levels.