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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Quantitation of Acrylamide in Foods by High-Resolution Mass Spectrometry
Troise, A.D. ; Fiore, A. ; Fogliano, V. - \ 2014
Journal of Agricultural and Food Chemistry 62 (2014)1. - ISSN 0021-8561 - p. 74 - 79.
liquid-chromatography - maillard reaction - potato-chips - lc-ms/ms - gc-ms - heated foodstuffs - dietary exposure - kinetic-model - fried potato - coffee
Acrylamide detection still represents one of the hottest topics in food chemistry. Solid phase cleanup coupled to liquid chromatography separation and tandem mass spectrometry detection along with GC-MS detection are nowadays the gold standard procedure for acrylamide quantitation thanks to high reproducibility, good recovery, and low relative standard deviation. High-resolution mass spectrometry (HRMS) is particularly suitable for the detection of low molecular weight amides, and it can provide some analytical advantages over other MS techniques. In this paper a liquid chromatography (LC) method for acrylamide determination using HRMS detection was developed and compared to LC coupled to tandem mass spectrometry. The procedure applied a simplified extraction, no cleanup steps, and a 4 min chromatography. It proved to be solid and robust with an acrylamide mass accuracy of 0.7 ppm, a limit of detection of 2.65 ppb, and a limit of quantitation of 5 ppb. The method was tested on four acrylamide-containing foods: cookies, French fries, ground coffee, and brewed coffee. Results were perfectly in line with those obtained by LC-MS/MS.
A stochastic model for predicting dextrose equivalent and saccharide composition during hydrolysis of starch by alpha-amylase
Besselink, T. ; Baks, T. ; Janssen, A.E.M. ; Boom, R.M. - \ 2008
Biotechnology and Bioengineering 100 (2008)4. - ISSN 0006-3592 - p. 684 - 697.
monte-carlo-simulation - bacillus-licheniformis - enzymatic-hydrolysis - soluble starch - kinetic-model - potato starch - amylopectin - amylolysis - enzymes - thermostability
A stochastic model was developed that was used to describe the formation and breakdown of all saccharides involved during -amylolytic starch hydrolysis in time. This model is based on the subsite maps found in literature for Bacillus amyloliquefaciens -amylase (BAA) and Bacillus licheniformis -amylase (BLA). Carbohydrate substrates were modeled in a relatively simple two-dimensional matrix. The predicted weight fractions of carbohydrates ranging from glucose to heptasaccharides and the predicted dextrose equivalent showed the same trend and order of magnitude as the corresponding experimental values. However, the absolute values were not the same. In case a well-defined substrate such as maltohexaose was used, comparable differences between the experimental and simulated data were observed indicating that the substrate model for starch does not cause these deviations. After changing the subsite map of BLA and the ratio between the time required for a productive and a non-productive attack for BAA, a better agreement between the model data and the experimental data was observed. Although the model input should be improved for more accurate predictions, the model can already be used to gain knowledge about the concentrations of all carbohydrates during hydrolysis with an -amylase. In addition, this model also seems to be applicable to other depolymerase-based systems
Production of glucose syrups in highly concentrated systems
Veen, M.E. van der; Goot, A.J. van der; Boom, R.M. - \ 2005
Biotechnology Progress 21 (2005)2. - ISSN 8756-7938 - p. 598 - 602.
enzymatic-hydrolysis - alpha-glucosidase - kinetic-model - wheat-starch - glucoamylase - optimization - mechanism - extruder - reactor
We have investigated the hydrolysis of maltodextrins in a high concentration (up to 70%), by means of enzymatic and acid catalysis. The study revealed that the equilibrium compositions of the catalyzed reactions were kinetically determined by the selectivity of the catalyst, the substrate concentration and the reaction time. A model comprising a set of two kinetic equations was used to describe the hydrolysis and condensation reactions of glucoamylase-catalyzed reactions, even to highly concentrated systems. Increased substrate concentration resulted in the formation of more condensation products. The enzyme inhibition was low and was found to be independent of the substrate concentration.
Maillard reactions and increased enzyme inactivation during oligosaccharide synthesis by a hyperthermophilic glycosidase
Bruins, M.E. ; Hellemond, E.W. van; Janssen, A.E.M. ; Boom, R.M. - \ 2003
Biotechnology and Bioengineering 81 (2003)5. - ISSN 0006-3592 - p. 546 - 552.
thermostable beta-glycosidases - high-temperature process - pyrococcus-furiosus - kinetic-model - glucosidase - hydrolysis - glycine - lactose - lysine - foods
The thermostable Pyrococcus furiosus beta-glycosidase was used for oligosaccharide production from lactose in a kinetically controlled reaction. Our experiments showed that higher temperatures are beneficial for the absolute as well as relative oligosaccharide yield. However, at reaction temperatures of 80degreesC and higher, the inactivation rate of the enzyme in the presence of sugars was increased by a factor of 2 compared to the inactivation rate in the absence of sugars. This increased enzyme inactivation was caused by the occurrence of Maillard reactions between the sugar and the enzyme. The browning of our reaction mixture due to Maillard reactions was modeled by a cascade of a zeroth- and first-order reaction and related to enzyme inactivation. From these results we conclude that modification of only a small number of amino groups already gives complete inactivation of the enzyme. (C) 2003 Wiley Periodicals.
Quantification of Melanoidin Concentration in Sugar-Casein Systems
Brands, C.M.J. ; Wedzicha, B.L. ; Boekel, M.A.J.S. van - \ 2002
Journal of Agricultural and Food Chemistry 50 (2002). - ISSN 0021-8561 - p. 1178 - 1183.
maillard reaction-products - mass-spectrometry - color formation - kinetic-model - glucose - glycine - polymers - ion
Melanoidins are the final, brown, high molecular weight products of the Maillard reaction. The aim of the present study was to determine the average molar extinction coefficients of melanoidins formed in heated glucose-casein and fructose-casein systems. The value of the extinction coefficient can be used to translate spectrophotometrically measured browning (absorbance values) into melanoidin concentration. In the present study the melanoidins were quantified by measuring the concentration of sugar incorporated into the melanoidins, using C-14-labeled sugar. The extinction coefficient of the melanoidins remained constant during the observation period as the absorbance at 420 nm increased to approximate to8 units, and it was calculated to be 477 (+/-50) L mol(-1) cm(-1) in the glucose-casein reaction and 527 (+/-35) L mol(-1) cm(-1) in the fructose-casein reaction. This difference is not significant. An increase of the number of sugar molecules per reactive amino group during the heating of glucose-casein and the fructose-casein mixtures was observed by the radiochemical method as well as by microanalysis of the high molecular weight fraction.
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