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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    Enhancing the Antioxidant Activity of Technical Lignins by Combining Solvent Fractionation and Ionic-Liquid Treatment
    Majira, Amel ; Godon, Blandine ; Foulon, Laurence ; Putten, Jacinta C. van der; Cézard, Laurent ; Thierry, Marina ; Pion, Florian ; Bado-Nilles, Anne ; Pandard, Pascal ; Jayabalan, Thangavelu ; Aguié-Béghin, Véronique ; Ducrot, Paul Henri ; Lapierre, Catherine ; Marlair, Guy ; Gosselink, Richard J.A. ; Baumberger, Stephanie ; Cottyn, Betty - \ 2019
    ChemSusChem 12 (2019)21. - ISSN 1864-5631 - p. 4799 - 4809.
    antioxidants - biorefinery - green chemistry - ionic liquids - lignins

    A grass soda technical lignin (PB1000) underwent a process combining solvent fractionation and treatment with an ionic liquid (IL), and a comprehensive investigation of the structural modifications was performed by using high-performance size-exclusion chromatography, 31P NMR spectroscopy, thioacidolysis, and GC–MS. Three fractions with distinct reactivity were recovered from successive ethyl acetate (EA), butanone, and methanol extractions. In parallel, a fraction deprived of EA extractives was obtained. The samples were treated with methyl imidazolium bromide ([HMIM]Br) by using either conventional heating or microwave irradiation. The treatment allowed us to solubilize 28 % of the EA-insoluble fraction and yielded additional free phenols in all the fractions, as a consequence of depolymerization and demethylation. The gain of the combined process in terms of antioxidant properties was demonstrated through 2,2-diphenyl-1-picrylhydrazyl (DPPH.) radical-scavenging tests. Integrating further IL safety-related data and environmental considerations, this study paves the way for the sustainable production of phenolic oligomers competing with commercial antioxidants.

    A Review on the Effect of Drying on Antioxidant Potential of Fruits and Vegetables
    Kamiloglu, Senem ; Toydemir, Gamze ; Boyacioglu, Dilek ; Beekwilder, Jules ; Hall, Robert D. ; Capanoglu, Esra - \ 2016
    Critical Reviews in Food Science and Nutrition 56 (2016). - ISSN 1040-8398 - p. S110 - S129.
    antioxidants - ascorbic acid - carotenoids - Drying - fruits - polyphenols - vegetables

    The role of antioxidants in human nutrition has gained increased interest, especially due to their associated health beneficial effects for a number of chronic diseases, including cardiovascular diseases and certain types of cancer. Fruits and vegetables are perishable and difficult to preserve as fresh products. Dried fruits and vegetables can be easily stored, transported at relatively low cost, have reduced packing costs, and their low water content delays microbial spoilage. Air-, freeze-, microwave- and sun-drying are among the most thoroughly studied drying methods. This review provides an overview of recent findings on the effects of different drying techniques on major antioxidants of fruits and vegetables. In particular, changes in ascorbic acid, carotenoids, flavonoids, phenolic acids, total phenolics, and antioxidant activity are discussed in detail.

    Plant verdedigt zich vaak te goed tegen lichtstress : vrije radicalen, schadelijk maar ook nuttig
    Kaiser, M.E. ; Heuvelink, E. ; Kierkels, T. - \ 2016
    Onder Glas 13 (2016)3. - p. 12 - 13.
    horticulture - greenhouse horticulture - pot plants - anthurium - light intensity - defence mechanisms - adverse effects - shade plants - antioxidants - tuinbouw - glastuinbouw - potplanten - anthurium - lichtsterkte - verdedigingsmechanismen - nadelige gevolgen - schaduwplanten - antioxidanten
    Een plant heeft te maken met voortdurend wisselende lichtniveaus die soms zodanig hoog kunnen oplopen dat ze schade veroorzaken. Er bestaat een uitgebreid stelsel van verdedigingslinies op alle niveaus: blad, cel, celorganen en moleculair niveau. Soms is de voorbereiding op mogelijke lichtschade zo goed dat het productie kost.
    'Productie van rode algen kan winstgevend zijn' : Wim Voogt over onderzoek algenteelt
    Voogt, Wim - \ 2015
    algae - algae culture - greenhouse horticulture - dyes - antioxidants - cropping systems - biobased economy - biobased chemicals

    De algenteelt in een gesloten systeem in de kas is dusdanig intensief en kostbaar dat het ook een hoogwaardig product moet opleveren. De rode algen die in 2015 zijn gekweekt bij Wageningen UR Glastuinbouw voldoen daaraan. Ze bevatten een gewilde kleurstof die bovendien een krachtige antioxidant is. Dat kan op termijn goede inkomsten opleveren.

    Preliminary UHPLC–PDA–ESI-MS screening of light-accelerated autoxidation products of the tetrapyrrole biliverdin
    Weesepoel, Y.J.A. ; Gruppen, H. ; Vincken, J.P. - \ 2015
    Food Chemistry 173 (2015). - ISSN 0308-8146 - p. 624 - 628.
    spirulina-platensis - mass-spectrometry - c-phycocyanin - stability - preservatives - antioxidants - pigments
    The application of phycobiliproteins, e.g. blue C-phycocyanin, as natural water-soluble food colourants is emerging. The chromophore of these proteins comprises a number of tetrapyrroles (or phycocyanobilins), which have an extensive conjugated system, vulnerable to autoxidation. To assess the autoxidation products, a simplified model system was used in which the free tetrapyrrole biliverdin, instead of phycobiliprotein, was subjected to light-accelerated autoxidation. Degradation products of biliverdin were subsequently annotated by reversed-phase ultra-high performance liquid chromatography with a photo diode array and positive mode in-line electrospray ionization mass spectrometry. To facilitate the analysis of degradation products, autoxidation of the three methine bridges in biliverdin was mimicked in silico. It was found that both the peripheral and central methine bridges of biliverdin were susceptible to light-accelerated autoxidation. Scission products tentatively annotated with MS2 and MS3 were propionic acid-containing pyrroles. From this, it can be speculated that tetrapyrroles attached to phycobiliproteins are susceptible to autoxidative degradation.
    Plasma carotenoids, vitamin C, retinol and tocopherols levels and pancreatic cancer risk within the European Prospective Investigation into Cancer and Nutrition: A nested case-control study : Plasma micronutrients and pancreatic cancer risk
    Jeurnink, S.M. ; Ros, M.M. ; Leenders, M. ; Duijnhoven, F.J.B. van - \ 2015
    International Journal of Cancer 136 (2015)6. - ISSN 0020-7136 - p. E665 - E676.
    alpha-tocopherol - beta-carotene - serum - smoking - cohorts - antioxidants - consumption - calibration - population - metabolism
    Evidence of a protective effect of several antioxidants and other nutrients on pancreatic cancer risk is inconsistent. The aim of this study was to investigate the association for prediagnostic plasma levels of carotenoids, vitamin C, retinol and tocopherols with risk of pancreatic cancer in a case–control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC). 446 incident exocrine pancreatic cancer cases were matched to 446 controls by age at blood collection, study center, sex, date and time of blood collection, fasting status and hormone use. Plasma carotenoids (a- and ß-carotene, lycopene, ß-cryptoxanthin, canthaxanthin, zeaxanthin and lutein), a- and ¿-tocopherol and retinol were measured by reverse phase high-performance liquid chromatography and plasma vitamin C by a colorimetric assay. Incidence rate ratios (IRRs) with 95% confidence intervals (95%CIs) for pancreatic cancer risk were estimated using a conditional logistic regression analysis, adjusted for smoking status, smoking duration and intensity, waist circumference, cotinine levels and diabetes status. Inverse associations with pancreatic cancer risk were found for plasma ß-carotene (IRR highest vs. lowest quartile 0.52, 95%CI 0.31–0.88, p for trend¿=¿0.02), zeaxanthin (IRR highest vs. lowest quartile 0.53, 95%CI 0.30–0.94, p for trend¿=¿0.06) and a-tocopherol (IRR highest vs. lowest quartile 0.62, 95%CI 0.39–0.99, p for trend¿=¿0.08. For a- and ß-carotene, lutein, sum of carotenoids and ¿-tocopherol, heterogeneity between geographical regions was observed. In conclusion, our results show that higher plasma concentrations of ß-carotene, zeaxanthin and a-tocopherol may be inversely associated with risk of pancreatic cancer, but further studies are warranted.
    A novel integrative method for measuring body condition in ecological studies based on physiological dysregulation
    Milot, E. ; Cohen, A.A. ; Vézina, F. ; Buehler, D.M. ; Matson, K.D. ; Piersma, T. - \ 2014
    Methods in Ecology and Evolution 5 (2014)2. - ISSN 2041-210X - p. 146 - 155.
    mahalanobis distance - sexual selection - annual-cycle - trade-offs - shorebirds - birds - antioxidants - acclimation - adjustments - performance
    1.The body condition of free-ranging animals affects their response to stress, decisions, ability to fulfil vital needs and, ultimately, fitness. However, this key attribute in ecology remains difficult to assess, and there is a clear need for more integrative measures than the common univariate proxies. 2.We propose a systems biology approach that positions individuals along a gradient from a ‘normal/optimal’ to ‘abnormal/suboptimal’ physiological state based on Mahalanobis distance computed from physiological biomarkers. We previously demonstrated the validity of this approach for studying ageing in humans; here, we illustrate its broad potential for ecological studies. 3.As an example, we used biomarker data on shorebirds and found that birds with an abnormal condition had a lower maximal thermogenic capacity and higher scores of inflammation, with important implications for their ecology and health. Moreover, Mahalanobis distance captured a signal of condition not detected by the individual biomarkers. 4.Overall, our results on birds and humans show that individuals with abnormal physiologies are indeed in worse condition. Moreover, our approach appears not to be particularly sensitive to which set of biomarkers is used to assess condition. Consequently, it could be applied easily to existing ecological data sets. 5.Our approach provides a general, powerful way to measure condition that helps resolve confusion as to how to deal with complex interactions and interdependence among multiple physiological and condition measures. It can be applied directly to topics such as the effect of environmental quality on body condition, risks of health outcomes, mechanisms of adaptive phenotypic plasticity, and mechanisms behind long-term processes such as senescence.
    Plasma and dietary carotenoids and vitamines A,C and E and the risk of colon and rectal cancer in the European prospective investigation into cancer and nutrition
    Leenders, M. ; Leufkens, A.M. ; Siersema, P.D. ; Duijnhoven, F.J.B. van; Vrieling, A. ; Hulshof, P.J.M. - \ 2014
    International Journal of Cancer 135 (2014)12. - ISSN 0020-7136 - p. 2930 - 2939.
    serum alpha-tocopherol - colorectal-cancer - oxidative stress - physical-activity - epic project - antioxidants - retinol - health - cohort - biomarkers
    Carotenoids and vitamins A, C and E are possibly associated with a reduced colorectal cancer (CRC) risk through antioxidative properties. The association of prediagnostic plasma concentrations and dietary consumption of carotenoids and vitamins A, C and E with the risk of colon and rectal cancer was examined in this case-control study, nested within the European Prospective Investigation into Cancer and Nutrition study. Plasma concentrations of carotenoids (alpha- and beta-carotene, canthaxanthin, beta-cryptoxanthin, lutein, lycopene, zeaxanthin) and vitamins A (retinol), C and E (alpha-, beta- and gamma-and delta-tocopherol) and dietary consumption of beta-carotene and vitamins A, C and E were determined in 898 colon cancer cases, 501 rectal cancer cases and 1,399 matched controls. Multivariable conditional logistic regression models were performed to estimate incidence rate ratios (IRR) and corresponding 95% confidence intervals (CIs). An association was observed between higher prediagnostic plasma retinol concentration and a lower risk of colon cancer (IRR for highest quartile = 0.63, 95% CI: 0.46, 0.87, p for trend = 0.01), most notably proximal colon cancer (IRR for highest quartile = 0.46, 95% CI: 0.27, 0.77, p for trend = 0.01). Additionally, inverse associations for dietary beta-carotene and dietary vitamins C and E with (distal) colon cancer were observed. Although other associations were suggested, there seems little evidence for a role of these selected compounds in preventing CRC through their antioxidative properties.
    Direct quantification of carotenoids in low fat babyfoods via laser photoacoustics and colorimetric index a
    Doka, O. ; Ajtony, Z. ; Bicanic, D.D. ; Valinger, D. ; Vegvari, G. - \ 2014
    International Journal of Thermophysics 35 (2014)12. - ISSN 0195-928X - p. 2197 - 2205.
    reflectance spectroscopy - lycopene content - cultivars - products - antioxidants - retinol - disease - fruits - color - pulp
    Carotenoids are important antioxidants found in various foods including those for nutrition of infants. In this investigation, the total carotenoid content (TCC) of nine different commercially available baby foods was quantified using colorimetric index a * obtained via reflectance colorimetry (RC) and by laser photoacoustic spectroscopy (LPAS) at 473 nm. The latter requires a minimum of sample preparation and only a one time calibration step which enables practically direct quantification of TCC. Results were verified versus UV–Vis spectrophotometry (SP) as the reference technique. It was shown that RC and LPAS (at 473 nm) provide satisfactory results for a *, R 2 = 0.9925 and R 2 = 0.9972, respectively. Other color indices do not show a correlation with TCC. When determining the TCC in baby foods containing tomatoes, it is necessary to select a different analytical wavelength to compensate for the effect of lycopene’s presence in the test samples.
    Plasma carotenoids and vitamin C concentrations and risk of urothelial cell carcinoma in the European Prospective Investigation into Cancer and Nutrition
    Ros, M.M. ; Bueno-de-Mesquita, H.B. ; Kampman, E. ; Aben, K.K. ; Büchner, F.L. ; Jansen, E.H.J.M. ; Gils, C.H. van; Egevad, L. ; Overvad, K. ; Kiemeney, L.A. - \ 2012
    American Journal of Clinical Nutrition 96 (2012). - ISSN 0002-9165 - p. 902 - 910.
    bladder-cancer - beta-carotene - alpha-tocopherol - vegetable consumption - physicians health - controlled-trial - retinol - serum - fruit - antioxidants
    BACKGROUND: Published associations between dietary carotenoids and vitamin C and bladder cancer risk are inconsistent. Biomarkers may provide more accurate measures of nutrient status. OBJECTIVE: We investigated the association between plasma carotenoids and vitamin C and risk of urothelial cell carcinoma (UCC) in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition. DESIGN: A total of 856 patients with newly diagnosed UCC were matched with 856 cohort members by sex, age at baseline, study center, date and time of blood collection, and fasting status. Plasma carotenoids (a- and ß-carotene, ß-cryptoxanthin, lycopene, lutein, and zeaxanthin) were measured by using reverse-phase HPLC, and plasma vitamin C was measured by using a colorimetric assay. Incidence rate ratios (IRRs) were estimated by using conditional logistic regression with adjustment for smoking status, duration, and intensity. RESULTS: UCC risk decreased with higher concentrations of the sum of plasma carotenoids (IRR for the highest compared with the lowest quartile: 0.64; 95% CI: 0.44, 0.93; P-trend = 0.04). Plasma ß-carotene was inversely associated with aggressive UCC (IRR: 0.51; 95% CI: 0.30, 0.88; P-trend = 0.02). Plasma lutein was inversely associated with risk of nonaggressive UCC (IRR: 0.56; 95% CI: 0.32, 0.98; P-trend = 0.05). No association was observed between plasma vitamin C and risk of UCC. CONCLUSIONS: Although residual confounding by smoking or other factors cannot be excluded, higher concentrations of plasma carotenoids may reduce risk of UCC, in particular aggressive UCC. Plasma lutein may reduce risk of nonaggressive UCC.
    The glycemic elemental profile of trichosanthes dioica: a LIBS-based study
    Rai, P.K. ; Chatterji, S. ; Rai, N.K. ; Bicanic, D.D. ; Watal, G. - \ 2010
    Food Biophysics 5 (2010)1. - ISSN 1557-1858 - p. 17 - 23.
    diabetes-mellitus - insulin - antioxidants - management - succinate - glucose
    The scientific evaluation of the antidiabetic efficacy of aqueous extract of Trichosanthes dioica fruits on streptozotocin-induced diabetic rats is being presented. The graded doses of the extract, viz., 500, 750, 1,000, and 1,250 mg/kg body weight (bw), were administered orally, and it was observed that the blood glucose concentration decreased in a dose-dependent manner. The dose of 1,000 mg/kg bw showed the maximum fall of 23.8% and 19.1% in blood glucose level (BGL) during fasting BGL and glucose tolerance test (GTT) studies, respectively, of nondiabetic rats. Whereas in the case of subdiabetic and mild diabetic models, the same dose showed reduction in BGL of 22.0% and 31.4% during GTT. The study also involves the first use of laser-induced breakdown spectroscopy as a sensitive analytical tool to detect the elemental profile responsible for the antidiabetic activity of aqueous extract of T. dioica fruits that exhibits the antidiabetic activity. High intensities of Ca, Mg, and Fe indicate large concentrations of these elements in the extract, since according to Boltzmann’s distribution law, intensities are directly proportional to concentrations. The higher concentrations of these glycemic elements, viz. Ca, Mg, and Fe, are responsible for the antidiabetic potential of T. dioica as well as other plant already reported by our research group.
    Gezondheidswaarde van appel en peer
    Vreeburg, R.A.M. ; Sluis, A.A. van der - \ 2009
    De Fruitteelt 99 (2009)19. - ISSN 0016-2302 - p. 14 - 15.
    fruitteelt - fruitgewassen - appels - peren - gezondheidsvoedsel - vitaminen - antioxidanten - fruit growing - fruit crops - apples - pears - health foods - vitamins - antioxidants
    Algemeen wordt aangenomen dat groente en fruit gezond zijn voor de mens. Maar hoe onderbouwd is de gedachte eigenlijk dat appels en peren gezond zijn
    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.
    Antioxidants, oxidative stress, and cardiovascular diseases : cross-cultural comparisons and prospective cohort studies
    Buijsse, B. - \ 2008
    Wageningen University. Promotor(en): Daan Kromhout; Frans Kok, co-promotor(en): Edith Feskens. - [S.l. : S.n. - ISBN 9789085049609 - 135
    antioxidanten - plantaardige producten - groenten - vruchten - hart- en vaatziekten - intercultureel onderzoek - internationale vergelijkingen - epidemiologische onderzoeken - nederland - cacao - oxidatieve stress - kreta - antioxidants - plant products - vegetables - fruits - cardiovascular diseases - cross cultural studies - international comparisons - epidemiological surveys - netherlands - cocoa - oxidative stress - crete
    Background: Antioxidants in plant foods have been proposed to reduce the risk of cardiovascular diseases (CVD) by reducing oxidative stress. The objective was to confirm prospective studies on CVD and traditional antioxidants (beta-carotene, alpha-tocopherol), and to investigate emerging antioxidants (alpha-carotene, gamma-tocopherol, cocoa flavanols), and oxidative stress (enzyme activity of glutathione peroxidase-3) with CVD risk.
    Methods: In cross-cultural studies, the Cretan (Greece) and Zutphen (The Netherlands) cohorts of Seven Countries Study were compared with respect to long-term mortality of coronary heart disease (CHD), diet, and indicators of oxidative stress. In prospective cohort studies, data were used from the Zutphen Elderly Study (~500 men aged 65-84 y), the ‘Survey in Europe on Nutrition and the Elderly: a Concerted Action’ (SENECA, 1168 men and women aged 70-75 y), and the Minnesota Heart Survey (270 men and women aged 26-85 y).
    Results: The comparison between the Cretan and Zutphen cohorts revealed a 3-fold lower 40-year CHD mortality rate in Crete. This lower mortality in Crete was paralleled by a higher consumption of fruit, tomatoes, and olive oil, amongst others, and by a lower consumption of meat, poultry, and dairy. Consequently, the Cretan men had higher intakes of carotenoids, alpha-tocopherol, vitamin C, and dietary fiber, and lower intakes of trans and saturated fatty acids. This was confirmed at the age of ≥80 years, when the Cretan men had higher plasma concentrations of major dietary antioxidants (major carotenoids and alpha-tocopherol), a lower iron status, and a lower level of oxidative stress. In the Zutphen Elderly Study, the relative risk (RR) of 15-y CVD mortality for 1 standard deviation (SD) increase in dietary intake was 0.81 [95% confidence interval (CI): 0.66-0.99] for alpha-carotene and 0.80 (95% CI: 0.66-0.97) for beta-carotene. The intake of tocopherols was not related to CVD death. In SENECA, plasma concentrations of carotene (sum of alpha- and beta-carotene) were inversely related to CVD mortality (RR for 1 SD increase: 0.83; 95% CI: 0.70-1.00), but plasma concentrations of alpha-tocopherol were not. The daily use of 4 grams of cocoa, a rich source of flavanols, was related to a 3.7 mm Hg lower systolic (95% CI: –7.1 to –0.3) and a 2.1 mm Hg lower (95% CI: –4.0 to –0.2) diastolic blood pressure. The same amount of cocoa was also related to a 50% lower risk of 15-year CVD mortality (RR: 0.50; 95% CI: 0.32-0.78). Finally, in the Minnesota Heart Survey, the odds ratio of CVD mortality for the highest vs. the lowest quartile of glutathione peroxidase-3 activity was 0.42 (95% CI: 0.21-0.86). This inverse relation was confined to those with low concentrations of HDL cholesterol (odds ratio highest vs. lowest quartile: 0.17; 95% CI: 0.06-0.47).
    Conclusion: The Cretan Mediterranean diet is rich in antioxidants, which may partly contribute to the low observed CHD mortality. The findings on beta-carotene support previous observational studies suggesting that this carotenoid relates to a lower CVD risk. We showed that alpha-carotene is correlated with beta-carotene in the diet, and alpha-carotene was also related to a lower CVD mortality. The results on alpha-tocopherol are in line with the outcomes of clinical trials and do not indicate a role for this vitamin in lowering CVD mortality in elderly populations.
    Proceedings of the 2nd international symposium on natural preservatives in food, feed, and cosmetics : Amsterdam, the Netherlands, June 7-8, 2006
    Havkin-Frenkel, D. ; Dudai, N. ; Mheen, H.J.C.J. van der - \ 2008
    Leuven : International Society for Horticultural Science (Acta horticulturae 778) - ISBN 9789066057302 - 110
    conserveermiddelen - voedselconserveermiddelen - voer - cosmetica - natuurlijke producten - medicinale planten - antioxidanten - etherische oliën - aromatische gewassen - preservatives - food preservatives - feeds - cosmetics - natural products - medicinal plants - antioxidants - essential oils - aromatic plants
    Verwaarding reststroom uienbewerking
    Meeusen-van Onna, M.J.G. ; Schroot, J.H. ; Mulder, W.J. ; Elbersen, H.W. - \ 2008
    Wageningen : Agrotechnology & Food Sciences Group (ASFG nr. 886) - ISBN 9789085048503 - 155
    uien - oogstresten - verwerking - extractie - industriële toepassingen - compostering - verbranding - fermentatie - kleurstoffen in voedsel - antioxidanten - scheidingstechnologie - bioethanol - biobased economy - onions - crop residues - processing - extraction - industrial applications - composting - combustion - fermentation - food colourants - antioxidants - separation technology - bioethanol - biobased economy
    In opdracht van ZUVER heeft Wageningen Universiteit en Research Centre de mogelijkheden bekeken voor verwaarding van de reststroom die bij de uienbewerking vrijkomt. Tijdens het uienbewerkingsproces komt een continue reststroom vrij. Deze reststroom bedraagt voor alle uienbewerkingsbedrijven tezamen jaarlijks 16.800 tot 18.900 ton. De reststroom komt vrij tijdens drie verschillende deelprocessen: lossen, afstaarten en sorteren/verpakken. De samenstelling van de reststroom is bij ieder proces anders. De drie deelprocessen geven qua omvang de volgende reststromen: ¿ Lossen: 4.800 ton tot 5.400 ton ¿ Afstaarten: 9.600 ton tot 10.800 ton ¿ Sorteren: 2.400 ton tot 2.700 ton Op dit moment 2008 wordt de reststroom gecomposteerd en over het land uitgereden. Tegelijkertijd willen de uienbewerkingsbedrijven ook kijken naar afzetmogelijkheden met meer toegevoegde waarde. De reststroom bevat interessante componenten die mogelijk interessant zijn voor hoogwaardiger toepassingen. De droge bruine pellen zijn rijk aan onoplosbare vezels en ze bevatten relatief veel quercitine. De wortels en bolstoel bevatten relatief veel zwavelcomponenten die als geur- of smaakstof herkenbaar zijn. Mogelijk kan een mengsel van quercitine en de zwavelcomponenten toegepast worden als insecticide of herbicide. Dit zal afhangen van werkzaamheid, dosering en benodigde zuiverheid. Wanneer de reststroom wordt gescheiden in een grondfractie en een overige fractie zijn er meer mogelijkheden voor de reststroom in beeld. Er zijn dus voordelen van scheiding van de grond- en niet-grondfractie. Het scheiden net na het lossen gebeurt al op dit moment: dat is de losstroom. Voor een aanvullende scheidingsstap is vooral de droge scheidingstechnologie in beeld. Het gaat dan bijvoorbeeld om windziften. Immers op elk bedrijf staan al afzuiginstallaties . ZUVER wil via mechanische stappen de scheiding verder optimaliseren . Om deze scheidingstechnieken te implementeren is nog wel een kort onderzoekstraject noodzakelijk waarin de technische en economische haalbaarheid van een scheiding van grond en uienpellen (inclusief staarten) uitgezocht wordt. Op basis van de samenstelling van de reststroom uit de uienbewerking is een groot aantal toepassingen bedacht. Deze toepassingen zijn gegroepeerd Verwaarding reststroom uienbewerking naar toegevoegde waarde, waarbij het onderscheid in fertilizer (compost, bodemverbeteraar), fuel (energie), fibre (vezel), feed (veevoer), food (humane voeding), farma en other (overig) is gehanteerd. De potentiële toepassingen omvatten een groot scala aan producten, die sterk uiteenlopen waar het gaat om de toegevoegde waarde. Daarvan lijkt een aantal toepassingen aantrekkelijk voor de uienbewerkingsbedrijven. Deze opties zijn nader uitgewerkt. Het gaat daarbij om opties die al binnen handbereik liggen, zoals compostering. Daarnaast zijn er toepassingen waar enig aanvullend onderzoek noodzakelijk is zoals verbranding. De meer hoogwaardiger toepassingen als kleurstof, antioxidant fungicide en insecticide vergen ook verdere ontwikkeling (met partners). Voor deze meer hoogwaardiger toepassingen geldt dat bedrijven die actief zijn in deze markt interesse hebben in de producten die de uienbewerkingsbedrijven kunnen aanleveren. In een samenwerkingsverband kunnen de mogelijkheden voor de verdere productontwikkeling worden verkend.
    New methods for the screening of antioxidants in three Sideritis species
    Koleva, I. - \ 2007
    Wageningen University. Promotor(en): Aede de Groot, co-promotor(en): Teris van Beek; Jozef Linssen. - [S.l.] : S.n. - ISBN 9789085046851 - 197
    antioxidanten - sideritis - chemische samenstelling - hplc - gaschromatografie - analytische scheikunde - antioxidants - sideritis - chemical composition - hplc - gas chromatography - analytical chemistry
    This thesis describes the rapid and robust evaluation of antioxidant activity of complex mixtures such as plant extracts. The study was directed to establish the best screening and isolation procedures for components with antioxidative properties to ensure the development of an “algorithm” for studying natural antioxidants. Three different screening methods (the b-carotene bleaching test (BCBT), the headspace GC method (HS-GC) and the off-line radical scavenging assay with the DPPH radical (DPPH method) and various extraction schemes were used. Three plants from the genus Sideritis grown in Bulgaria (S. scardica, S. syriaca and S. montana) served as test species. The strengths and limitations of each method were illustrated by testing a number of extracts of different polarity. A novel HPLC-DPPH method to rapidly and sensitively pinpoint individual antioxidants in complex mixtures with as little as possible fractionation procedures was developed. The use of the alternative ABTS·+ radical cation made the method in most cases even more sensitive. The instrumental set-up and physico-chemical parameters of both methods were studied. The methods were successful for qualitative and semi-quantitative measurements of pure antioxidants and extracts. A review is under preparation on the use of on-line methods. As a result, a range of flavonoid-, phenylpropanoid- and iridoid glycosides were isolated. The radical scavenging activity of the isolated compounds by off- and on-line DPPH methods was studied. Three novel compounds were isolated: flavonoid glycosides luteolin-4'-methylether-7-O-[6'''-O-acetyl-β-D-allopyranosyl-(1-2)-β-D-glucopyranoside and hypolaetin-4'-methylether-7-O-[β-D-allopyranosyl-(1-2)-6''-O-acetyl-β-D-glucopyranoside, and iridoid glycoside 3''-O-p-coumaroyl-6''-O-acetyl melittoside from Sideritis species. Preliminary studies by the HS-GC method were applied to investigate how Sideritis extracts and pure components would behave in real systems: bulk oils and oil-in-water emulsions. Conjugated dienes and hexanal formation were monitored using rosmarinic acid and BHT as standards. They showed good inhibitory effects with regard to dienes and hexanal formation in both test systems.
    The combination of ascorbic acid 6-palmitate and [Fe III 3(µ3-O)]7+ as a catalyst for the oxidation of unsaturated lipids
    Micciche, F. ; Long, G.J. ; Shahin, A.M. ; Grandjean, F. ; Ming, W. ; Haveren, J. van; Linde, R. van der - \ 2007
    Inorganica Chimica Acta 360 (2007)2. - ISSN 0020-1693 - p. 535 - 545.
    mixed-valence - carboxylate complexes - iron - autoxidation - peroxidation - coordination - antioxidants - perchlorates - initiation - chemistry
    Recently, iron 2-ethylhexanoate (Fe-eh, 1) in combination with ascorbic acid 6-palmitate (AsA6p) has been reported as a good catalytic system for the oxidation of ethyl linoleate (EL), an unsaturated lipid. In response to the fascinating chemistry of this bio-inspired iron-based catalyst the structure of Fe-eh, and the effect of AsA6p on it, have been studied. Fe-eh was found to be a trinuclear oxido-centered iron(III) cluster of general formula . The Mössbauer spectra of 1 indicate that the trinuclear iron core is not symmetric as the spectra exhibit two equivalent iron(III) sites and one unique iron(III) site. Variable temperature magnetic measurements indicate that the three iron centers are antiferromagnetically coupled. Upon the addition of AsA6p to complex 1 a new species (2), which has not yet been completely identified, is formed. Mössbauer spectroscopy indicates, however, that 2 is a mixed-valence cluster which probably has an iron-core that differs in symmetry from 1. The reduction of 1 to 2 was also monitored in time by electrospray ionization mass spectrometry, revealing that the reduction reaction is kinetically dependent on the molar ratio AsA6p/Fe-eh. Based on these results and other available information, a general mechanism for the oxidation of EL under the effect of the combination of AsA6p/Fe-eh is proposed
    Intake of polyunsaturated fatty acids and vitamin E reduces the risk of developing amyotrophic lateral sclerosis
    Veldink, J.H. ; Kalmijn, S. ; Groeneveld, G.J. ; Wunderink, W. ; Köster, B. ; Vries, J.H.M. de; Luyt, J. van der; Wokke, J.H.J. ; Berg, L.H. - \ 2007
    Journal of neurology, neurosurgery and psychiatry 78 (2007). - ISSN 0022-3050 - p. 367 - 371.
    motor-neuron disease - dietary-intake - antecedent events - amino-acids - foods - als - questionnaire - antioxidants - netherlands - flavonoids
    Background: To assess whether the premorbid dietary intake of fatty acids, cholesterol, lutamate, or anti- oxidants was associated with the risk of developing ALS. Methods: Patients referred to our clinic during the one-year period, 2001-2002, who had definite, probable or possible ALS according to El Escorial criteria, without a familial history of ALS, were asked to participate in a case-control study (132 patients and 220 healthy controls). A food-frequency questionnaire was used to assess dietary intake concerning the nutrients of interest. Multivariate logistic regression analysis was performed with adjustment for confounding factors (sex, age, level of education, energy intake, body mass index, and smoking). Results: High intake of polyunsaturated fatty acid (PUFA) and vitamin E was significantly associated with a reduced risk of developing ALS (PUFA: OR = 0.4, 95% CI = 0.2 - 0.7, p = 0.001; vitamin E: OR = 0.4, 95% CI = 0.2 - 0.7, p = 0.001). PUFA and vitamin E appeared to act synergistically, because in a combined analysis the trend OR for vitamin E was further reduced from 0.67 to 0.37 (p = 0.02), and for PUFA from 0.60 to 0.26 (p = 0.005), with a significant interaction term (p = 0.03). The intake of flavonols, lycopene, vitamin C, vitamin B2, glutamate, calcium, or phytoestrogens was not associated with ALS. onclusion: A high intake of PUFAs and vitamin E was associated with a 50% to 60% decreased risk of developing ALS, and these nutrients appear to act synergistically
    Screening, isolation and evaluation of antioxidative compounds from Geranium macrorrhizum, Potentilla fruticosa and Rhaponticum carthamoides
    Miliauskas, G. - \ 2006
    Wageningen University. Promotor(en): Ernst Sudhölter, co-promotor(en): Teris van Beek; Jozef Linssen. - [S.l.] : S.n. - ISBN 9789085044871 - 160
    antioxidanten - extractie - geranium macrorrhizum - potentilla fruticosa - rhaponticum carthamoides - biologische eigenschappen - antioxidants - extraction - geranium macrorrhizum - potentilla fruticosa - rhaponticum carthamoides - biological properties
    Food molecules (lipids, proteins, carbohydrates) can be widely involved in oxidation reactions. These reactions, caused by so called reactive oxygen species (ROS) are a major cause of food deterioration. In the case of lipid containing foods this process is defined as rancidity. Significant changes can occur in product colour, texture and nutritive value. Eventually the oxidation can result in complete spoilage. Oxidation reactions caused by ROS also play an important role in the ageing processes of living organisms and are associated with numerous diseases, like coronary heart disease, cancer, cataracts, ageing. Although protective mechanisms exist both in living cells and in foods, in many cases there is a need to strengthen this mechanism. A daily intake of antioxidants can prevent or delay problems caused by ROS.

    The research described in this study is aimed at the evaluation of several plant extracts as a possible source of food antioxidants.An initial screening for radical scavenging activity of extracts from medicinal and aromatic plants namely Salvia sclarea , Salvia glutinosa , Salvia pratensis , Salvia officinalis, Lavandula angustifolia , Calendula officinalis , Matricaria recutita , Echinacea purpurea , Rhaponticum carthamoides , Juglans regia , Melilotus officinalis , Geranium macrorrhizum and Potentilla fruticosa has been performed using DPPH and ABTS radical scavenging assays. Of these extracts Geranium macrorrhizum and Potentilla fruticosa possessed the highest radical scavenging activity in both assays, higher than that of the Salvia officinalis extract.

    In further steps of this study the structures of the radical scavenging compounds present in leaf extracts ofGeranium macrorrhizum, in blossoms extracts ofPotentilla fruticosaand leaf extracts of Rhaponticum carthamoides were elucidated.

    The radical scavenging activity of the isolated compounds from Geranium macrorrhizum and Potentilla fruticosa was measured using DPPH·and ABTS·+scavenging assays and compared with the activity of rosmarinic acid and Trolox.

    A quantitative comparison of the major antioxidant compounds in different botanical parts of Geranium macrorrhizum and Potentilla fruticosa was also made.

    A hyphenated LC-DAD-SPE-NMR set-up in combination with on-line radical scavenging detection was used for the identification of radical scavenging compounds from Rhaponticum carthamoidesextracts. The technique enabled selective detection and identification of individual radical scavenging compounds without any prior off-line chromatographic steps. One of identified a new natural compound. Its radical scavenging activity was tested against DPPH radical and was found to be weaker than that of the reference antioxidants rosmarinic acid and Trolox.

    Antioxidant activity of all plant fractions from Geranium macrorrhizum and Potentilla fruticosa was assessed by model system assays and in real food systems consisting of edible oil or fermented sausages.

    A preliminary safety evaluation of some plant extracts has been conducted (enzymatic oxidation assay;effects against singlet oxygen caused erythrocyte hemolysis;mutagenicity evaluation) andindicated the plant extracts not to be genotoxic or mutagenic.

    Research on natural products, like plant antioxidants, demands the application of various analytical techniques. Apart from state-of-the-art analytical instruments, a lot of specific techniques needed to be applied at certain stages, e.g. on-line radical scavenging detection of individual plant constituents in complex plant mixtures. These DPPH/ABTS assays coupled on-line to liquid chromatography-diode array detection set-ups have been developed earlier at the Laboratory of Organic Chemistry of Wageningen University. Expansion of these assays by coupling a mass spectrometer to the system was one part of the methodological research.

    The developed system enabled a quick analysis (simultaneous separation, isolation-identification and detection of radical scavenging activity) of complex Ginkgo and rosemary extracts.

    The hyphenated LC-DAD-SPE-NMR system is another powerful technique for compound isolation and structure elucidation in complex mixtures. The investigation of the application of LC-DAD-SPE-NMR with a semi-preparative HPLC column and comparison of the obtained results with those of an analytical column was described in the thesis.

    It is concluded that extracts from Geranium and Potentilla are unlikely to be a new source of antioxidants for lipophilic food products. Extracts proved to be effective in assays with polarmedia,however their application in such products is also unlikely. Reasons are problems, like odour and colour of the extracts, and the complex extraction procedure.
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