Halina Kozlowska

Bioactive compounds in the cereal grains before and after hydrothermal processing

Abstract The studies aimed at explaining the role of cereals as the source of biologically active compounds. Wheat ( Triticum aestivum L . ) cv. Almari, barley ( Hordeum vulgare L . ) cv. Gregor, rye ( Secale cereale L . ) cv. Dankowskie Zlote and oat ( Avena sativa L . ) cv. Slawko were used in the study. The content of the following biologically active compounds was determined: inositol phosphates, tocopherols, tocotrienols, reduced glutathione, melatonin, phenolic acids as well as the content of microelements (Cu, Zn, Mn and Se). The behaviour of these compounds under extrusion cooking (process temperatures of 120–160–200°), which was taken as a model of hydrothermal processes, was analyzed. Extrusion caused a significant decrease in all the compounds tested, except for phenolic ones. A decrease in inositol hexaphosphate, depending on the species of cereal, was from 4 to 50%, in tocopherols and tocotrienols, from 63 to 94%, in reduced glutathione, from 20 to 50%, and in melatonin, from 17 to 63%. An increase in the content of phenolic acids (free and released from ester bonds) reached from 200 to 300%.

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.

Natural fermentation of lentils : Influence of time, concentration, and temperature on the kinetics of hydrolysis of inositol phosphates

Lentil (Lens culinaris var vulgaris) flour was naturally fermented for 96 h at various conditions of concentration (79, 150 and 221 g litre -1 ) and temperature (28°C, 35°C and 42°C). The content of total inositol phosphates (IP-total) and individual inositol phosphates (hexa- (IP 6 ), penta- (IP 5 ), tetra- (IP 4 ) and tri- (IP 3 ) phosphates) were analysed to establish the changes of these compounds during natural fermentation of lentils. The preparation of the lentil suspension brought about 16-27% reduction of the total inositol phosphates. At the end of 96 h of natural fermentation maximum IP loss (70-75%) was achieved for an experiment carried out at minimum concentration. For IP 6 , the largest decrease was achieved at the highest temperature, the fermentation condition that also brought about the highest IP 5 content.

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.

Evolution of soluble carbohydrates during the development of pea, faba bean and lupin seeds.

Seeds of pea (Pisum sativum L. cv. Ergo), faba bean (Vicia faba ssp. minor Harz., cv. Tibo) and yellow pea lupin (Lupinus luteus L. cv. Juno) were sampled at different days after flowering (DAF) and their content of soluble carbohydrates was determined: Analysis of samples showed thatmyo-inositol, fructose, glucose, galactose and sucrose were found in high abundance early in development and their content decreased gradually during maturation. α-Galactosides, which includes the content of raffinose, stachyose and verbascose, started to appear later in seed development, at 37 DAF in peas, 40 DAF in faba beans and 45 DAF in lupins. Their accumulation increased considerably during seed growth, and the maximum content was obtained in mature seeds; 3.8% in peas, 4.5% in faba beans and 10.4% in lupins. Results obtained for these sugars during seed development were fitted to modelling curves in order to predict sugar content at different development stages.

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.