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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Biological potential of extracts of the wild edible Basidiomycete mushroom Grifola frondosa
Klaus, A. ; Kozarski, M. ; Vunduk, N. ; Todorovic, N. ; Jakovlejevic, D. ; Zizak, Z. ; Pavlovic, V. ; Levic, S. ; Niksic, M. ; Griensven, L.J.L.D. van - \ 2015
Food Research International 67 (2015). - ISSN 0963-9969 - p. 272 - 283.
rapid colorimetric assay - antimicrobial properties - chemical-characterization - plant-extracts - immunomodulating activities - antioxidative activities - polysaccharide extracts - antibacterial activity - ganoderma-lucidum - agaricus-bisporus
Partially purified polysaccharides (FP) and hot alkali extract (FNa) obtained from fruiting bodies of the wild basidiomycete Grifola frondosa were examined for their antimicrobial, antioxidant and cytotoxic activity. The structural properties of FP and FNa samples were investigated by FT-IR and high resolution 1H- and 13C-NMR spectroscopy. From a group of various G - and G + bacteria the antibacterial effects were highest against the G + B. cereus. FNa was the better antioxidant shown by the lower EC50 values of DPPH scavenging ability, ferric-reducing antioxidant power and ferrous ion-chelating ability. Ferric-reducing antioxidant power and ferrous ion-chelating ability were mostly linked to total polysaccharides, total- and ß-glucan content, as well as total protein content. Both extracts displayed a moderate dose dependent antiproliferative action towards malignant human breast cancer MDA-MB-453, cervical adenocarcinoma HeLa and myelogenous leukemia K562 cells not observed in the non cancer derived MRC-5 fibroblasts. The highest effect was found in HeLa cells for FP extract. The mean diameter of Ca-alginate bead loading FP was 960.7 µm while the mean diameter of beads encapsulating FNa extract was 1051.7 µm
Polysaccharies of higher fungi: Biological role, structure and antioxidative activity
Kozarski, M.S. ; Klaus, A. ; Niksic, M. ; Griensven, L.J.L.D. van; Vrvic, M.M. ; Jakovljevic, D.M. - \ 2014
Hemijska Industrija 68 (2014)3. - ISSN 0367-598X - p. 305 - 320.
radical scavenging activities - activated protein-kinases - ganoderma-lucidum - agaricus-brasiliensis - lentinus-edodes - beta-glucan - feruloyl oligosaccharides - chemical-characterization - butylated hydroxyanisole - medicinal mushrooms
The fungal polysaccharides attract a lot of attention due to their multiple challenging bio-logical properties, such as: anti-tumor, anti-viral, anticomplementary, anticoagulant, hypo-lipidemic, immunomodulatory and immune-stimulatory activities, which all together make them suitable for application in many quite distinctive areas, such as food industry, bio-medicine, cosmetology, agriculture, environmental protection and waste water manage-ment. This article presents results with respect to biological properties, structure and pro-cedures related to the isolation and activation of polysaccharides of higher fungi. It is considered and presented along with a review of the critical antioxidative activity and pos-sible influence of the structural composition of polysaccharide extracts (isolated from these higher fungi) upon their antioxidative properties.
The edible mushroom Laetiporus sulphureus as potential source of natural antioxidants
Klaus, A. ; Kozarski, M. ; Niksic, M. ; Jakovljevic, D. ; Todorovic, N. ; Stefanoska, I. ; Griensven, L.J.L.D. van - \ 2013
International Journal of Food Sciences and Nutrition 64 (2013)5. - ISSN 0963-7486 - p. 599 - 610.
ganoderma-lucidum - feruloyl oligosaccharides - chemical-characterization - polysaccharide extracts - agaricus-bisporus - diabetic-rats - fruit-bodies - components - complexes - amylose
Hot water extract (LN), partially purified polysaccharides (LP) and hot alkali extracted polysaccharides (LNa) obtained from fruiting bodies of the wild basidiomycete Laetiporus sulphureus were examined for their antioxidant activities. LNa was the most active antioxidant, as shown by the median effective concentrations (EC50 values) of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (0.5 +/- 0.2 mg/ml), reducing power (4.0 +/- 0.3 mg/ml) and ferrous ion-chelating ability (1.5 +/- 0.1 mg/ml). LNa contained the highest level of alpha-glucan (17.3 +/- 1.2 g/100 g dw), whereas LP contained mostly beta-glucans (66.8 +/- 1.3 g/100 g dw). The prevalent monosaccharide in all extracts was glucose. The EC50 values of all three antioxidant activity assays were well-correlated with the alpha-glucan content. Strong and significant correlation was found between total phenolic compounds and DPPH scavenging ability and also reducing power. The three investigated extracts (at concentrations of 0.1-10 mg/ml) were not toxic to HTR-8/SVneo trophoblast cell line.
Roasting Effects on Formation Mechanisms of Coffee Brew Melanoidins
Bekedam, E.K. ; Loots, M.J. ; Schols, H.A. ; Boekel, M.A.J.S. van; Smit, G. - \ 2008
Journal of Agricultural and Food Chemistry 56 (2008)16. - ISSN 0021-8561 - p. 7138 - 7145.
molecular-weight melanoidins - zinc-chelating substance - chemical-characterization - antioxidant activity - liquid-chromatography - beverages - beans - green - acids - food
The effect of the roasting degree on coffee brew melanoidin properties and formation mechanisms was studied. Coffee brew fractions differing in molecular weight (Mw) were isolated from green and light-, medium-, and dark-roasted coffee beans. Isolated fractions were characterized for their melanoidin, nitrogen, protein, phenolic groups, chlorogenic acid, quinic acid, caffeic acid, and sugar content. It was found that the melanoidin level in all fractions correlated with both the nitrogen and the protein content. The melanoidin level also correlated with the phenolic groups¿ level and ester-linked quinic acid level. It was concluded that proteins and chlorogenic acids should be primarily involved in melanoidin formation. Initial roasting, from green to light-roasted beans, especially led to the formation of intermediate Mw (IMw) melanoidins when compared to high Mw (HMw) melanoidins. Indications were found that this IMw melanoidin formation is mainly due to Maillard reactions and chlorogenic acid incorporation reactions between chlorogenic acids, sucrose, and amino acids/protein fragments. Additionally, it was found that prolonged roasting predominantly led to formation melanoidins with a high Mw. Furthermore, arabinogalactans seem to be relatively more involved in melanoidin formation than galactomannans. It was hypothesized that chromophores may be formed or attached through the arabinose moiety of arabinogalactan proteins (AGP). Finally, it could be concluded that galactomannans are continuously incorporated in AGP-melanoidins upon roasting.
Low Molecular Weight Melanoidins in Coffee Brew
Bekedam, E.K. ; Roos, E. ; Schols, H.A. ; Boekel, M.A.J.S. van; Smit, G. - \ 2008
Journal of Agricultural and Food Chemistry 56 (2008)11. - ISSN 0021-8561 - p. 4060 - 4067.
maillard reaction-products - chemical-characterization - antioxidant activity - colored compounds - roasted coffee - arabica beans - model systems - polysaccharides - xylose - lysine
Analysis of low molecular weight (LMw) coffee brew melanoidins is challenging due to the presence of many non-melanoidin components that complicate analysis. This study focused on the isolation of LMw coffee brew melanoidins by separation of melanoidins from non-melanoidin components that are present in LMw coffee brew material. LMw coffee fractions differing in polarity were obtained by reversed-phase solid phase extraction and their melanoidin, sugar, nitrogen, caffeine, trigonelline, 5-caffeoylquinic acid, quinic acid, caffeic acid, and phenolic groups contents were determined. The sugar composition, the charge properties, and the absorbance at various wavelengths were investigated as well. The majority of the LMw melanoidins were found to have an apolar character, whereas most non-melanoidins have a polar character. The three isolated melanoidin-rich fractions represented 56% of the LMw coffee melanoidins and were free from non-melanoidin components. Spectroscopic analysis revealed that the melanoidins isolated showed similar features as high molecular weight coffee melanoidins. All three melanoidin fractions contained ~3% nitrogen, indicating the presence of incorporated amino acids or proteins. Surprisingly, glucose was the main sugar present in these melanoidins, and it was reasoned that sucrose is the most likely source for this glucose within the melanoidin structure. It was also found that LMw melanoidins exposed a negative charge, and this negative charge was inversely proportional to the apolar character of the melanoidins. Phenolic group levels as high as 47% were found, which could be explained by the incorporation of chlorogenic acids in these melanoidins
Electron Spin Resonance (ESR) Studies on the Formation of Roasting-Induced Antioxidative Structures in Coffee Brews at Different Degrees of Roast
Bekedam, E.K. ; Schols, H.A. ; Cämmerer, B. ; Kroh, L.W. ; Boekel, M.A.J.S. van; Smit, G. - \ 2008
Journal of Agricultural and Food Chemistry 56 (2008)12. - ISSN 0021-8561 - p. 4597 - 4604.
chemical-characterization - thermal-degradation - chlorogenic acids - model systems - melanoidins - capacity - foods - beverages - green
The antioxidative properties of coffee brew fractions were studied using electron spin resonance spectroscopy using 2,2,6,6-tetramethyl-1-piperidin-1-oxyl (TEMPO) and Fremy¿s salt (nitrosodisulfonate) as stabilized radicals. TEMPO was scavenged by antioxidants formed during roasting and not by chlorogenic acid, whereas Fremy¿s salt was scavenged by all antioxidants tested including chlorogenic acid. The stabilized radical TEMPO allowed the exclusive measurement of roasting-induced antioxidants. The roasting-induced antioxidant activity of coffee brews increased with increasing degree of roast, and most of these antioxidants were formed during the initial roasting stage. The majority of these roasting-induced antioxidants were present in the high molecular weight fractions, indicating that the formation of these antioxidants preferably occurs at specific high molecular weight structures, likely being arabinogalactan and/or protein moieties which might be part of the melanoidin complex. It was found that chlorogenic acids most probably do not lose their antioxidant activity and phenolic characteristics upon incorporation in coffee melanoidins. The parameter fast reacting antioxidants (FRA) was introduced as an alternative for the antioxidative potential. FRA levels showed that coffee fractions rich in roasting-induced antioxidants exposed their antioxidant activity relatively slowly, which must be a consequence of its complex structure. Finally, the melanoidin content and the roasting-induced antioxidant activity showed a positive and linear correlation for the coffee brew fractions, showing that roasting-induced antioxidants are present within melanoidins. This is the first time that the formation of roasting-induced antioxidants could be directly correlated with the extent of Maillard reaction and melanoidin formation in a complex product such as coffee.
Incorporation of Chlorogenic Acids in Coffee Brew Melanoidins
Bekedam, E.K. ; Schols, H.A. ; Boekel, T. van; Smit, G. - \ 2008
Journal of Agricultural and Food Chemistry 56 (2008)6. - ISSN 0021-8561 - p. 2055 - 2063.
antioxidant activity - chemical-characterization - roasted coffee - degradation - lactones - beans - chromatography - phenols - systems
The incorporation of chlorogenic acids (CGAs) and their subunits quinic and caffeic acids (QA and CA) in coffee brew melanoidins was studied. Fractions with different molecular weights, ionic charges, and ethanol solubilities were isolated from coffee brew. Fractions were saponified, and the released QA and CA were quantified. For all melanoidin fractions, it was found that more QA than CA was released. QA levels correlated with melanoidin levels, indicating that QA is incorporated in melanoidins. The QA level was correlated with increasing ionic charge of the melanoidin populations, suggesting that QA may contribute to the negative charge and consequently is, most likely, not linked via its carboxyl group. The QA level correlated with the phenolic acid group level, as determined by Folin-Ciocalteu, indicating that QA was incorporated to a similar extent as the polyphenolic moiety from CGA. The QA and CA released from brew fractions by enzymes confirmed the incorporation of intact CGAs. Intact CGAs are proposed to be incorporated in melanoidins upon roasting via CA through mainly nonester linkages. This complex can be written as MelCA¿QA, in which Mel represents the melanoidin backbone, CA represents CA nonester-linked to the melanoidin backbone, and ¿QA represents QA ester-linked to CA. Additionally, a total of 12% of QA was identified in coffee brew, whereas only 6% was reported in the literature so far. The relevance of the additional QA on coffee brew stability is discussed.
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
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