Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Isolation, identification and activity of natural antioxidants from sweet grass (Hierochloe odorata), costmary (Chhrysanthemum balsamita) and horehound (Marrubium vulgare), cultivated in Lithuania
Pukalskas, A. - \ 2008
Wageningen University. Promotor(en): Aede de Groot, co-promotor(en): Teris van Beek; Jozef Linssen. - [S.l.] : S.n. - ISBN 9789085049821 - 137
antioxidanten - natuurlijke producten - extractie - fysicochemische eigenschappen - litouwen - antioxidants - natural products - extraction - physicochemical properties - lithuania
Food products are susceptible to oxidation processes. Oxidation of lipids (fat) is the major cause of food deterioration however also proteins and carbohydrates can be affected. To prevent or retard this process, antioxidants are used. With regard to foods, more and more natural products are preferred by consumers so new natural sources of compounds able to retard oxidation processes and prevent spoilage of food products are continuously investigated.
The research described in this study is aimed at the evaluation of several herbs as possible sources of food antioxidants. An initial screening of extracts from roman camomile, tansy, sweet grass, costmary, sea-buckthorn and sage for antioxidant activity in rapeseed oil has been performed Sweet grass and sage acetone extracts retarded oxidation processes in oil best.
Sweet grass was chosen for further investigation as the herb having the highest antioxidant activity. Two other herbs, namely horehound and costmary were further selected for the evaluation of their antioxidant activity in different assays. At first preliminary fractionation of the selected herb extracts was performed. Fractions were tested in three different assays: -carotene oxidation, DPPH• reduction and rapeseed oil oxidation. The experiments did not provide any straightforward answers, which fractions contained the most active antioxidants. Different assays gave different results. More polar fractions were more active in model systems like DPPH• while in the edible oil assay these fractions acted as weak antioxidants, or some even exhibited a prooxidation effect. Acetone extracts performed better than methanol-water extracts in retarding oil oxidation probably due to their higher compatibility with the medium or the more non-polar nature of the contained analytes.
In further steps the structures of the radical scavenging compounds present in extracts of sweet grass, horehound and costmary were elucidated. Two compounds, namely 5,8-dihydroxybenzopyranone and 5-hydroxy-8-O--D-glucopyranosyl benzopyranone were isolated and identified from sweet grass extract. Both compounds were identified for the first time as natural products. Four compounds, namely 5-O-caffeoyl quinic acid (chlorogenic acid), 3,5-dicaffeoyl quinic acid, 5,7,4'-trihydroxy-3',8-dimethoxy flavone and 5,7,3',4'-tetrahydroxy-3,8-dimethoxyflavonol were identified in costmary extracts. These compounds are quite common in plant kingdom. However, they have not previously been isolated from costmary. Five compounds, namely 5,8-dihydroxy-7,4-dimethoxy flavone, 7-O--glucopyranosyl luteolin, 7-O--glucuronyl luteolin, verbascoside and forsythoside B were isolated from horehound extracts. These compounds are common in the Labiatae family. Their radical scavenging activity was measured using DPPH• and ABTS•+ scavenging assays and compared with the activity of rosmarinic acid and Trolox.
An on-line HPLC-DPPH-DAD-NMR system for the rapid identification of compounds in complex mixtures was developed. The developed system was tested on commercial rosemary extract and six compounds were identified without the need to isolate them. This proved that simultaneous detection and identification of radical scavengers is possible.
Several solvents, namely hexane, acetone ant ethanol and their combinations were tested for their suitability to extract all known radical scavengers from sweet grass, costmary and horehound. It was found that initial extraction of the plant material with hexane increased the concentrations of radical scavengers in the following extraction stages.
Visit to the Nemunas River area (Lihuania) - autumn 2007
Mulder, J.R. ; Weijschede, T.J. - \ 2008
Wageningen : Alterra (Alterra-rapport 1706) - 81
waterbeheer - bezoeken - hydrologie - vragenlijsten - overstromingen - hoogwaterbeheersing - litouwen - houding van boeren - waterstand - kennis van boeren - water management - visits - hydrology - questionnaires - floods - flood control - lithuania - farmers' attitudes - water level - farmers' knowledge
In het voorjaar van 2007 is besloten om het gebied van de Nemunas rivier op de grens van Litouwen en Kalinigrad te bezoeken om boeren te interviewen over het omgaan met hoog water in een vrijwel onbedijkt gebied. Daarnaast is een beeld gevormd van de overstromingsvlakten. Dit rivierengebied overstroomt twee keer per jaar, waarbij de boerderijen en nederzettingen in totaal zo’n twee maanden van de bewoonde wereld zijn afgesloten. Het blijkt dat de noodzaak om samen te werken vanwege het hoge water niet wordt gevoeld
Management and restoration of nature 2000 sites in the Dovine River Basin
Zingstra, H.L. ; Gulbinas, Z. ; Kitnaes, K. ; Querner, E.P. - \ 2006
Wageningen : Wageningen International - 16
natuurbescherming - litouwen - habitatrichtlijn - kaderrichtlijn water - nature conservation - lithuania - habitats directive - water framework directive
Analysis of water management measures in the Dovine River Basin, Lithuania; possibilities to restore a natural water regime
Povilaitis, A. ; Querner, E.P. - \ 2006
Wageningen : Alterra (Alterra-rapport 1370) - 67
waterbeheer - rivieren - meren - litouwen - wetlands - analyse - maatregelen - water management - rivers - lakes - lithuania - analysis - measures
The Zuvintas Lake, located in southern Lithuania in the basin of the Dovine River is one of the biggest lakes and oldest nature reserves of the country. Both the lake as well as the adjacent wetland is a potential Site of Community Interest (SCI) according to the EU Habitats Directive. However, the changes in the hydrology of the Dovine River Basin, because of large scale melioration and water management works carried out in the 20th century, have significantly changed the water regime as well as a decrease in biodiversity of Zuvintas Lake and surrounding wetlands. In order to prevent the ongoing deterioration of Zuvintas Lake and adjacent wetlands solutions have to be found at a basin level. Therefore, various scenarios to evaluate the impact of water management alternatives in the Dovine River basin have been analyzed to get insight in the impact of changes on the water regime in Zuvintas Lake and adjacent wetlands. For these scenarios the SIMGRO model was used.
Antioxidant activity of Potentilla fruticosa
Miliauskas, G. ; Beek, T.A. van; Venskutonis, P.R. ; Linssen, J.P.H. ; Waard, P. de; Sudhölter, E.J.R. - \ 2004
Journal of the Science of Food and Agriculture 84 (2004)15. - ISSN 0022-5142 - p. 1997 - 2009.
radical scavenging activity - plant-extracts - flavonoids - lithuania - pomace - herbs
The molecular structures of the radical scavenging compounds present in extracts of Potentilla fruticosa blossoms were elucidated and the antioxidant activities of various extracts were determined. The activities of the different fractions were monitored by off-line and on-line RP-HPLC DPPH. and ABTS(.+) scavenging methods. Twelve compounds were isolated and identified, namely ellagic acid, catechin, quercetin-3-beta-glucopyranoside, quercetin-3-beta-galactopyranoside, quercetin-3-beta-rutinoside, quercetin-3-beta-glucuronopyranoside, quercetin-3-alpha-arabinofuranoside, kaempferol-3-beta-rutinoside, kaempferol-3-O-beta-(6"-O-(E)-p-coumaroyl)glucopyranoside, rhamnetin-3-beta-glucopyranoside and rhamnetin-3-beta-galactopyranoside. The radical scavenging activity of each isolated compound was measured using DPPH. and ABTS(.+) assays and compared with the activity of rosmarinic acid. Catechin and ellagic acid were found to be the most active radical scavengers. The antioxidant properties of plant fractions were assessed in model systems by measuring superoxide anion and hydrogen peroxide scavenging, beta-carotene bleaching, hexanal production in edible oil, peroxide formation, and the increase in UV absorbance in the course of oxidation. (C) 2004 Society of Chemical Industry.
Antioxidative activity of Geranium macrorrhizum
Miliauskas, G. ; Beek, T.A. van; Venskutonis, P.R. ; Linssen, J.P.H. ; Waard, P. de - \ 2004
European Food Research and Technology 218 (2004)3. - ISSN 1438-2377 - p. 253 - 261.
radical scavenging activity - plant-extracts - rapeseed oil - flavonoids - l. - identification - lithuania - tannins - leaves - pomace
The composition of radical-scavenging compounds from Geranium macrorrhizum leaves was analyzed and the antioxidative activities of various extracts was determined. Seven compounds, namely gallic acid, ellagic acid, 4-galloyl quinic acid, the flavonoid quercetin and three of its glycosides, quercetin-3-beta-glucopyranoside, quercetin-3-beta-galactopyranoside and quercetin-4'-beta-glucopyranoside were isolated and identified in the various fractions. The radical-scavenging activity of the isolated compounds was measured using DPPHcircle and ABTS(circle+) scavenging assays and compared with the activity of rosmarinic acid. Quercetin-3-glucopyranoside and quercetin-3-galactopyranoside showed the highest antioxidative capacities. Antioxidative activities of all plant fractions were assessed by model system tests (superoxide anion and hydrogen peroxide scavenging) and by oxidation tests (beta-carotene bleaching, peroxide value, UV absorbance and headspace-gas chromatography hexanal determination). The ethanol-butanol fraction of the plant possessed the highest activity in most of the tests.
Engels raaigras: een stimulans voor de melkveehouderij in Litouwen
Wouters, B. ; Schukking, S. - \ 2002
Praktijkkompas. Rundvee 16 (2002)3. - ISSN 1570-8586 - p. 14 - 15.
melkveehouderij - agrarische bedrijfsvoering - melkveebedrijven - demonstratiebedrijven, landbouw - melkproductie - melkopbrengst - diervoedering - veevoeding - rundveevoeding - voedergewassen - voederplanten - grassen - grasbestand - graslandbeheer - graslandverbetering - weiden - lolium perenne - litouwen - landen van de europese unie - lidmaatschap - dairy farming - farm management - dairy farms - demonstration farms - milk production - milk yield - animal feeding - livestock feeding - cattle feeding - fodder crops - fodder plants - grasses - herbage - grassland management - grassland improvement - pastures - lithuania - european union countries - membership
Met steun vanuit Nederland is op zeven praktijkbedrijven de bedrijfsvoering verbeterd. De introductie van Engels raaigras droeg daar sterk aan bij.
Aroma of some plants cultivated in Lithuania : composition, processing and release
Bylaite, E. - \ 2000
Agricultural University. Promotor(en): A.G.J. Voragen; R.P. Venskutonis; J.P. Roozen. - S.l. : S.n. - ISBN 9789058082329 - 182
plantkunde - aroma - etherische oliën - asteraceae - etherische oliehoudende planten - litouwen - aromatische gewassen - botany - aroma - essential oils - asteraceae - essential oil plants - lithuania - aromatic plants

In this study, some factors affecting the aroma of some plants of the families Umbelliferae and Asteraceae were evaluated. The composition of the aromas is influenced by several factors: plant family, harvesting time, anatomical part of plant, method used to isolate volatiles, cultivar, fertilisers used for the growing of plant, cultivation site. The yield of caraway fruits varies over a wide range depending on fertiliser content, cultivation area and the cultivar itself. The trends for the accumulation of essential oils differ between the families in yield and composition. Seeds and flowers of lovage ( Umbelliferae ) possess the highest yields of oil. In the leaves of lovage seasonal changes are less significant than in the stems. In leaves and flowers of costmary ( Asteraceae ) the highest oil content is obtained before full flowering, while their stems possess only negligible amount of volatiles. Various anatomical parts of lovage showed differences in flavour release measured by the dynamic headspace method. The effluents from a gas chromatography column were characterised by a sniffing panel, which attributed descriptors to the recognised constituents.

Liquid essential oils can be processed by emulsification and encapsulation with milk proteins. Stability of essential oil-in-water emulsions can be improved either by adding soybean phosphatidylcholine and/or by increasing its protein concentration. Adsorption of the protein from the aqueous phase at the oil/water interface was studied by applying ellipsometry. Essential oil of caraway was encapsulated by milk derivatives either alone or combined with carbohydrates. Partial replacement of whey protein concentrate increases the retention of volatiles during spray drying and enhances the protective properties of solidified capsules against oxidation and the release of volatiles during the timed period. The structural features of spray- dried capsules indicated that good physical protection is provided to the caraway essential oil.

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