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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    Chemical characterization and biological activity of Chaga (Inonotus obliquus) a medicinal "mushroom"
    Glamoclija, J. ; Ciric, A. ; Nikolic, M. ; Fernandes, A. ; Barros, L. ; Calhelha, R.C. ; Ferreira, I.C.F.R. ; Sokovic, M. ; Griensven, L.J.L.D. van - \ 2015
    Journal of Ethnopharmacology 162 (2015). - ISSN 0378-8741 - p. 323 - 332.
    pseudomonas-aeruginosa - swarming motility - in-vitro - biofilm formation - edible mushrooms - social evolution - aqueous extract - gene-expression - hot-water - antioxidant
    ETHNOPHARMACOLOGICAL RELEVANCE: In Russian traditional medicine, an extract from the mushroom Inonotus obliquus (Fr.) Pil´at is used as an anti-tumor medicine and diuretic. It has been reported that Inonotus obliquus has therapeutic effects, such as anti-inflammatory, immuno-modulatory and hepatoprotective effects. This study was designed to investigate the chemical composition and biological properties of aqueous and ethanolic extracts of Inonotus obliquus from Finland, Russia, and Thailand. Their antioxidative, antimicrobial, and antiquorum properties were tested as well as the cytotoxicity on various tumor cell lines. MATERIALS AND METHODS: The tested extract was subjected to conventional chemical study to identified organic acids and phenolic compounds. Antioxidative activity was measured by several different assays. Antimicrobial potential of extracts was tested by microdilution method, and antiquorum sensing activity and antibiofilm formation of Inonotus obliquus extracts was tested on Pseudomonas aeruginosa. Cytotoxicity of the extracts was tested on tumor cells (MCF-7, NCI-H460, HeLa and HepG2) and non-tumor liver cells primary cultures. RESULTS: Oxalic acid was found as the main organic acid, with the highest amount in the aqueous extract from Russia. Gallic, protocatechuic and p-hydroxybenzoic acids were detected in all samples. Inonotus obliquus extracts showed high antioxidant and antimicrobial activity. Extracts were tested at subMIC for anti-quorum sensing (AQS) activity in Pseudomonas aeruginosa and all extracts showed definite AQS activity. The assays were done using twitching and swarming of bacterial cultures, and the amount of produced pyocyanin as QS parameters. All the extracts demonstrated cytotoxic effect on four tumor cell lines and not on primary porcine liver cells PLP2. CONCLUSIONS: As the Inonotus obliquus presence in Chaga conks is limited, further purification is necessary to draw quantitative conclusions. The presence of AQS activity in medicinal mushrooms suggests a broader anti-infectious disease protection than only immunomodulatory effects.
    Food safety management systems performance in the lamb production chain
    Oses, S.M. ; Luning, P.A. ; Jacxsens, L. ; Jaime, I. ; Rovira, J. - \ 2012
    Food Control 25 (2012)2. - ISSN 0956-7135 - p. 493 - 500.
    escherichia-coli o157-h7 - beef processing plants - haccp-based approach - lactic-acid - steam pasteurization - pathogenic bacteria - bovine carcasses - spray washes - supply chain - hot-water
    This study describes a performance measurement of implemented food safety management system (FSMS) along the lamb chain using an FSMS-diagnostic instrument (FSMS-DI) and a Microbiological Assessment Scheme (MAS). Three slaughterhouses, 1 processing plant and 5 butcher shops were evaluated. All the actors along the lamb chain achieved a moderate risky contextual situation, operating in a basic-average FSMS, which was not enough to obtain a good food safety output. Different suggestions are advised for each actor along the lamb chain for improvements towards higher FSMS activity levels or lower risk levels in context characteristics. The combined assessment is a useful tool to identify the possible causes of poor food safety performance in the lamb chain using few sampling locations, saving time and money.
    High Molecular Weight Melanoidins from Coffee Brew
    Bekedam, E.K. ; Schols, H.A. ; Boekel, T. van; Smit, G. - \ 2006
    Journal of Agricultural and Food Chemistry 54 (2006)20. - ISSN 0021-8561 - p. 7658 - 7666.
    chemical-characterization - maillard reaction - liquid-chromatography - espresso coffee - roasted coffee - arabica coffee - foam stability - amino-acids - hot-water - green
    The composition of high molecular weight (HMw) coffee melanoidin populations, obtained after ethanol precipitation, was studied. The specific extinction coefficient (Kmix) at 280, 325, 405 nm, sugar composition, phenolic group content, nitrogen content, amino acid composition, and non-protein nitrogen (NPN) content were investigated. Results show that most HMw coffee melanoidins are soluble at high ethanol concentrations. The amino acid composition of the HMw fractions was similar, while 17% (w/w) of the nitrogen was NPN, probably originating from degraded amino acids/proteins and now part of melanoidins. A strong correlation between the melanoidin content, the NPN, and protein content was found. It was concluded that proteins are incorporated into the melanoidins and that the degree of chemical modification, for example, by phenolic groups, determines the solubility of melanoidins in ethanol. Although the existence of covalent interaction between melanoidins and polysaccharides were not proven in this study, the findings suggest that especially arabinogalactan is likely involved in melanoidin formation. Finally, phenolic groups were present in the HMw fraction of coffee, and a correlation was found with the melanoidin concentration
    Structural features of acelated galactomannans from green Coffea arabica Beans
    Oosterveld, A. ; Coenen, G.J. ; Vermeulen, N.C.B. ; Voragen, A.G.J. ; Schols, H.A. - \ 2004
    Carbohydrate Polymers 58 (2004)4. - ISSN 0144-8617 - p. 427 - 434.
    hot-water - chemical characterization - xylo-oligosaccharides - polysaccharides - extracts
    Polysaccharides were extracted from green Coffea arabica beans with water (90 °C, 1 h). Galactomannans were isolated from the water extract using preparative anion-exchange chromatography. Almost all of the galactomannans eluted in two neutral populations, while almost all of the arabinogalactans bound to the column, indicating that these arabinogalactans contain charged groups. Analysis of the molecular weight distribution of the two neutral populations showed that they differ in their molecular weight. Further characterization of these neutral populations by NMR and by MALDI-TOF MS after enzymatic degradation with an endo-mannanase, showed the presence of acetyl groups linked to the galactomannans, a feature not previously described for this type of polysaccharides from coffee beans. It was found that the high molecular weight (ca. 2000 kDa) neutral fraction was highly substituted both with galactose residues and acetyl groups, while the low molecular weight (ca. 20 kDa) population was much less substituted. Based on these results it can be concluded that at least two distinctly different populations of galactomannans are present in green coffee beans. It was also shown that the degradation of the galactomannans from green coffee beans with an endo-mannanase from A. niger is hindered by the presence of acetyl groups.
    Effect of roasting on the carbohydrate composition of Coffea arabica beans.
    Oosterveld, A. ; Voragen, A.G.J. ; Schols, H.A. - \ 2003
    Carbohydrate Polymers 54 (2003)2. - ISSN 0144-8617 - p. 183 - 192.
    rich pectic polysaccharides - sugar-beet pulp - chemical characterization - hot-water - arabinose - green
    Coffee beans (arabica) with different degrees of roast were sequentially extracted with water (90 °C, 1 h), water (170 °C, 30 min), and 0.05 M NaOH (0 °C, 1 h). The amount and composition of polysaccharides, oligosaccharides and monosaccharides in the extracts and residues were analyzed. The results were compared with the composition of the same batch of green arabica coffee beans. Although part of our results were already reported in rather fragmented studies, this study gives a more complete overview of the amount and composition of unextractable polymers, extractable polymers, oligomers, monomers, and their conversion into (non-sugar) degradation products as a function of their degree of roast. It was found that most carbohydrates in the roasted coffee bean were present as polysaccharides (extractable or unextractable). The fact that only a small part of the carbohydrates in the extracts were recovered as oligomer and even less as monomers, showed that oligomers and especially monomers were converted very rapidly into Maillard and pyrolysis products. Cellulose remains unextractable and its solubility was not affected by the degree of roast. Galactomannans were also mainly present as unextractable polymers in green beans, but were solubilized to a large extent with increasing degrees of roast. The arabinogalactans in the roasted bean were highly soluble at the extraction conditions used. The arabinose as present as side-chains in the arabinogalactans were found to be more susceptible to degradation at more severe roasting conditions than the galactans. Also evidence was found that populations of arabinogalactans with very different ara:gal ratios exist in the roasted beans as well as in the green beans.
    Extraction and characterization of polysaccharides from green and roasted Coffea arabica beans.
    Oosterveld, A. ; Harmsen, H. ; Voragen, A.G.J. ; Schols, H.A. - \ 2003
    Carbohydrate Polymers 52 (2003)3. - ISSN 0144-8617 - p. 285 - 296.
    rich pectic polysaccharides - sugar-beet pulp - hot-water - arabinose
    Polysaccharides were sequentially extracted from green and roasted Coffea arabica beans with water (90 °C), EDTA, 0.05, 1, and 4 M NaOH and characterized chemically. Additionally, the beans were subjected to a single extraction with water at 170 °C. Green arabica coffee beans contained large proportions of 1¿4-linked mannans, of which on average 1 in every 23 mannopyranose residues was branched with single unit galactose side-chains at O-6. A part of these galactomannans could be extracted relatively easy with water and EDTA. These galactomannans were found to have a relatively high degree of branching (gal:man1:8) and a relatively low molecular weight in comparison to the remaining galactomannans (gal:man1:15–24). Additionally, 1¿3-linked galactans, heavily branched at O-6 with side-chains containing arabinose and galactose residues, were present in the green coffee beans, as well as smaller amounts of pectins, cellulose, and xyloglucans. Roasting resulted in a loss of 8% of the dry weight. This could be partly explained by the relatively high percentage of sugars which was lost during the roasting process, most probably as a result of conversion into, e.g. Maillard and pyrolysis products. After roasting the extractability of polysaccharides was increased significantly. A decrease in the degree of branching as well as a decrease in molecular weight of arabinogalactans, galactomannans, and xyloglucans was observed after roasting.
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