Time filter

Source Type

Havlíčkův Brod, Czech Republic

Lachman J.,Czech University of Life Sciences | Hamouz K.,Czech University of Life Sciences | Musilova J.,Slovak University of Agriculture | Hejtmankova K.,Czech University of Life Sciences | And 5 more authors.
Food Chemistry | Year: 2013

The impact of peeling and three cooking treatments (boiling, baking and microwaving) on the content of selected phytochemicals in white-, yellow-, red- and purple-fleshed potatoes was investigated. Ascorbic acid and chlorogenic acid contents were determined by HPLC-DAD, total anthocyanin content by pH-differential spectrophotometry, glycoalkaloid, α-chaconine and α-solanine contents by HPLC-ESI/MS/MS. All cooking treatments reduced ascorbic and chlorogenic acid contents, total glycoalkaloids, α-chaconine and α-solanine with the exception of total anthocyanins. The losses of ascorbic and chlorogenic acids were minimised with boiling and total anthocyanin levels retained the highest. Boiling of peeled tubers decreased contents of total glycoalkaloids (α-chaconine and α-solanine) and appeared as the most favourable among the three tested methods. Moreover, due to higher initial levels, red- and purple-fleshed cultivars retained higher amounts of antioxidants (ascorbic acid, chlorogenic acid and total anthocyanin) after boiling and may be healthier as compared with white or yellow cultivars. © 2012 Elsevier Ltd. All rights reserved.

Hejtmankova K.,Czech University of Life Sciences | Kotikova Z.,Czech University of Life Sciences | Hamouz K.,Czech University of Life Sciences | Pivec V.,Czech University of Life Sciences | And 2 more authors.
Journal of Food Composition and Analysis | Year: 2013

The objective of this two-year study was to determine the main carotenoids in 15 varieties of potatoes (Solanum tuberosum L.) with different flesh colour - white, yellow, red and purple and two varieties of Solanum phureja. Content of total anthocyanins in pigmented potatoes was also determined and compared with the carotenoid level. Potatoes were cultivated in two localities with different soil-climatic conditions. Content of carotenoids and anthocyanins was affected by variety and locality. Moreover, carotenoid content was influenced by the growing year. Content of total carotenoids ranged from 0.779 to 13.3mg/kg dry matter (DM). The main carotenoid was lutein in all varieties (54-93%) furthermore violaxanthin, neoxanthin, zeaxanthin and β-carotene were identified in most of the analysed samples. The highest carotenoid content was found in S. phureja varieties. The pigmented varieties Blaue Anneliese, Violetta, Olivia (all purple) and H.B. Red (red) showed comparable carotenoid level with the yellow-fleshed variety Agria; other pigmented varieties contained similar carotenoid levels as white-fleshed varieties. Content of total anthocyanins ranged from 210 to 2419mg/kg DM and correspond to flesh colour intensity. A weak correlation between carotenoids and anthocyanins was found (r2=0.33). Thus some coloured varieties could be a good source of both studied phytochemicals. © 2013 Elsevier Inc.

Kodrik D.,Academy of Sciences of the Czech Republic | Kludkiewicz B.,Academy of Sciences of the Czech Republic | Navratil O.,Academy of Sciences of the Czech Republic | Skokova Habustova O.,Academy of Sciences of the Czech Republic | And 4 more authors.
Applied Biochemistry and Biotechnology | Year: 2013

Several recombinant derivatives of serine protease inhibitor called silk protease inhibitor 2 (SPI2), which is a silk component in Galleria mellonella (Lepidoptera, Insecta), were prepared in the expression vector Pichia pastoris. Both the native and the recombinant protease inhibitors were highly active against subtilisin and proteinase K. The synthetic SPI2 gene with Ala codon in the P1 position was fused with mGFP-5 to facilitate detection of the transgene and its protein product. A construct of the fusion gene with plant regulatory elements (promoter 35S and terminator OCS) was inserted into the binary vector pRD400. The final construct was introduced into Agrobacterium tumefaciens that was then used for genetic transformation of the potato variety Velox. The transgene expression was monitored with the aid of ELISA employing polyclonal antibody against natural SPI2. In vitro tests showed increased resistance to the late blight Phytophthora infestans in several transformed lines. No effect was seen on the growth, mortality, life span or reproduction of Spodoptera littoralis (Lepidoptera, Insecta) caterpillars, while feeding on transformed potato plants expressing the fusion protein, indicating that the transformed potatoes may be harmless to non-target organisms. © 2013 Springer Science+Business Media New York.

Navratil O.,Academy of Sciences of the Czech Republic | Bucher P.,Potato Research Institute Ltd. | Vacek J.,Potato Research Institute Ltd.
Czech Journal of Genetics and Plant Breeding | Year: 2012

Cold-stored potato tubers gradually accumulate reducing sugars. A proposed reason is a cold-induced blocking of glycolysis. The introduction and expression of the bacterial gene Lbpfk coding for cold-tolerant phosphofructokinase might counteract this effect. We have recently introduced this gene into several Czech potato cultivars. The obtained transgenic lines were then tested for three years in field trials. In 17 transgenic lines derived from two of the cultivars we have investigated the accumulation of reducing sugars during two and four months of cold storage. Although in all transgenic lines the sugar content still increased between the 2 nd and the 4 th month of cold-storage, the level of reducing sugars was in all transgenic lines after both two and four months of cold storage considerably lower than in the original cultivars. The extent of sugar accumulation was also influenced by the parental genotype. No significant differences in sugar accumulation were observed between the transgenic lines from the same parent.

Polzerova H.,Potato Research Institute Ltd. | Patzak J.,Hop Research Institute Co. | Greplova M.,Potato Research Institute Ltd.
Plant Cell, Tissue and Organ Culture | Year: 2011

Variability of 31 somatic hybrids of Solanum pinnatisectum Dun. with Solanum tuberosum L. for leaf morphology, plant vigor, resistance to Phytophthora infestans, ploidy level, and cytoplasm type was evaluated in vitro. The composition of these somatic hybrids was as follows: [S. pinnatisectum Dun. (2n = 2x = 24; cytoplasmic type Wγ) + S. tuberosum L. (2n = 4x = 48; cytoplasmic type Tß)]. Based on leaf morphology and plant growth vigor, plants were divided into three groups, including plants close to tbr parent with unlobed leaves, small plants with scarcely dissected leaves, and vigorous plants with asymmetrically and pinnately lobed leaves. Nine of the somatic hybrids were found to be highly resistant to P. infestans. Somatic hybrids were either tetraploid or hexaploid, with hexaploids being predominant. The cytoplasm of somatic hybrids was either Tßγ or Wßγ, with Tßγ being more common. Overall, in contrast to leaf morphology and growth vigor, level of resistance to P. infestans was not related to either ploidy level or type of cytoplasm. These findings demonstrate that early in vitro selection of promising hybrids can be useful in breeding programs. © 2010 Springer Science+Business Media B.V.

Discover hidden collaborations