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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    New tools in modulating Maillard reaction from model systems to food
    Troise, A.D. - \ 2015
    Wageningen University. Promotor(en): Vincenzo Fogliano, co-promotor(en): Claire Berton-Carabin; P. Vitaglione. - Wageningen : Wageningen University - ISBN 9789462575455 - 129
    maillard-reactie - maillard-reactieproducten - modulatie - controle - inkapselen - olijfolie - melk - emulsies - modellen - voedsel - gereedschappen - maillard reaction - maillard reaction products - modulation - control - encapsulation - olive oil - milk - emulsions - models - food - tools
    New tools in modulating Maillard reaction from model systems to food

    The Maillard reaction (MR) supervises the final quality of foods and occupies a prominent place in food science. The first stable compounds, the Amadori rearrangement products (APs) and Heyns rearrangement products (HPs), represent the key molecules from which a myriad of reactions takes place and each of them contributes to the formation of Maillard reaction end-products (MRPs) or advanced glycation end products (AGEs).

    Several papers have dealt with the control of the MR in foods ranging from the thermal loading reduction, to the use of alternative process technologies, reactants impact or enzymes, as well as to the monitoring of the end-products formation by multiresponse modeling. The strategies used up to now aim at common goals: the reduction of potentially toxic compounds and the promotion of desired molecules formation as well as flavor, aroma, color and texture attributes. In other words the ultimate target is the promotion of food quality by tuning the MR.

    This thesis introduces four alternative strategies that are able to control the final extent of the MR in foods.

    The possibility to segregate reactants by encapsulating some minor components and thus delaying the MR was highlighted in Chapter 2. The encapsulation of sodium chloride, ascorbic acid, PUFA and iron inside hydrophobic capsules was used as a possible example: the core material release over the time delayed the reaction rates.

    The results obtained through the treatment with the enzyme fructosamine oxidase (Faox) I and II which is able to deglycate free Amadori products and capitalize the local unfolding of lysine peptide bound residues were reported in Chapter 3. Data showed that Faox can reduce the formation ofNε-(Carboxymethyl)-L-lysine and bound hydroxymethylfurfural in model system and in low lactose milk.

    The effects obtained with the addition of spray-dried olive oil mill wastewaters in milk was illustrated in Chapter 4. This ingredient acts as a source of phenylethanoids, which can trap a-hydroxycarbonyls and a-dicarbonyls and can form adducts with amino groups after the oxidation of phenolic rings into quinone. The use of this functional ingredient before milk thermal treatment resulted in a reduction of off-flavor, reactive carbonyls species and bound MRPs.

    The possibilities offered by the location of MR reactants in microemulsion was investigated in Chapter 5. The oil/water partition coefficient of amino acids played a key role in the formation of Amadori compounds. The anchoring effect of tricaprylin and Tween 20 toward aliphatic amino acids in microemulsion systems was evaluated and compared to a control aqueous solution of amino acids and glucose. Results confirmed the hypothesis: the higher the partition coefficient the lower the formation of aliphatic amino acids Amadori compounds.

    All of the four proposed strategies involved location and interaction of reagents, reactants, intermediates and final products. As a result each strategy depicted a specific route for the control of the final extent of the MR. Many steps are still necessary to scale up these methodologies into the food production chain, however new ways for obtaining foods of superior quality have been paved.

    Kinetic modelling of the Maillard reaction between proteins and sugars
    Brands, C.M.J. - \ 2002
    Wageningen University. Promotor(en): M.A.J.S. van Boekel; W.M.F. Jongen. - S.l. : S.n. - ISBN 9789058085917 - 127
    maillard-reactie - maillard-reactieproducten - kinetica - maillard reaction - maillard reaction products - kinetics
    Keywords: Maillard reaction, sugar isomerisation, kinetics, multiresponse modelling, brown colour formation, lysine damage, mutagenicity, casein, monosaccharides, disaccharides, aldoses, ketoses

    The aim of this thesis was to determine the kinetics of the Maillard reaction between proteins and sugars, taking into account other simultaneously occurring sugar reactions. Model systems of foods, consisting of the protein casein and various sugars in a buffered solution, were studied. The reaction conditions were varied, covering relevant heating conditions for foods. The kinetics of the reactions were studied by means of multiresponse modelling.

    The main reaction routes that were established in heated sugar-casein systems were (i) isomerisation of the aldose sugars into ketose sugars and vice versa, (ii) degradation of the sugar into carboxylic acids and unidentified products and (iii) the Maillard reaction between the sugar (degradation products) and the protein. In the Maillard reaction, the aldose sugars (like glucose and lactose) reacted with thee-amino group of lysine residues of the protein to form the Amadori product. Under the conditions studied in this thesis (90-130°C; pH 6.8) it was shown that ketose sugars (like fructose and lactulose) themselves were not reactive in the Maillard reaction. Therefore, the expected Heyns compound could not be detected. The degradation products of the sugars and Amadori products reacted in the Maillard reaction with either thee-amino group of the lysine residues or the guanidine groups of the arginine residues of the protein to form the brown-coloured melanoidins. The Maillard reactivity of the sugar degradation products was found to be much higher than that of the aldose sugars themselves. The formation of these reaction intermediates was, however, highly temperature dependent. The reaction mechanism of disaccharide sugars was roughly in accordance with that of monosaccharide sugars, with the difference that some sugar degradation pathways were hindered by the glycosidic bound sugar while others were favoured.

    The multiresponse modelling approach as used in this thesis appeared to be a very powerful tool to unravel complicated reaction routes as occur in the Maillard reaction. The observed differences in reaction mechanism and reaction rate between the various studied sugars can be used to direct food quality aspects like browning, loss of nutritive value due to lysine damage and formation of mutagenic compounds.

    Free-living nematodes from nature reserves in Costa Rica. 3. Araeolaimida
    Zullini, A. ; Loof, P.A.A. ; Bongers, T. - \ 2002
    Nematology 4 (2002)6. - ISSN 1388-5545 - p. 709 - 724.
    descriptions - new species - redescriptions - Plectus - Costa Rica - Araeolaimidae - free living nematodes - nematoda - taxonomy - beschrijvingen - nieuwe soorten - herbeschrijvingen - Plectus - Costa Rica - Araeolaimidae - vrijlevende nematoden - Nematoda - taxonomie
    Seven species of Araeolaimida were found in soil, moss and freshwater habitats of tropical forests in Costa Rica. Three are described as new. Anonchus pulcher n. sp. is characterised by slender body, lip region demarcated by a depression, presence of ca 45-60 sublateral glands on each side of the body and monoprodelphic female genital apparatus. Paraplectonema americanum n. sp. lacks somatic setae, the stoma is 3.0-3.4 lip region diameter long, the female rectum measures 26 μm, the male tail 137-153 μm, presence of ten to 11 male supplements, spicula 28-30 μm long, gubernaculum of complicated shape with a caudal apophysis. Chronogaster costaricae n. sp. is characterised by absence of longitudinal incisures, rows of spines, crystalloids and vacuolated glandular bodies, terminus with open mucro with one or two basal spines. The species redescribed, either briefly for well known, or more extensively for less well known, species are: Plectus patagonicus de Man, 1904; P. indicus Khera, 1972; Chronogaster serrulata Loof, 1973 and C. cameroonensis Heyns & Coomans, 1984.
    Redescription of Xiphinema nigeriense Luc, 1961 and observations on X. dihysterum Lamberti et al., 1995 and X. mampara Heyns, 1979 (Nematoda: Dorylaimida)
    Coomans, A. ; Loof, P.A.A. ; Luc, M. - \ 1999
    Nematology 1 (1999)1. - ISSN 1388-5545 - p. 85 - 94.
    Aporcelaimus Thorne and Swanger 1936 (Nematoda): proposed designation of Dorylaimus superbus de Man, 1880 as the type species.
    Loof, P.A.A. ; Heyns, J. - \ 1997
    Bulletin of Zoological Nomenclature 54 (1997)2. - ISSN 0007-5167 - p. 80 - 82.
    Nygolaimus Cobb, 1913 (Nematoda: proposed designation of Dorylaimus brachyuris de Man,1880 as the type species.
    Loof, P.A.A. ; Heyns, J. - \ 1996
    Bulletin of Zoological Nomenclature 53 (1996). - ISSN 0007-5167 - p. 18 - 20.
    Variation in Mesodorylaimus potus Heyns, 1963 syn. M. globiceps Loof, 1964 (Dorylaimida)
    Loof, P.A.A. ; Heyns, J. - \ 1983
    Nematologica 28 (1983). - ISSN 0028-2596 - p. 370 - 371.
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