Martin W A Verstegen

Publications (2)1.44 Total impact

• Article: Fermentation characteristics of polysaccharide fractions extracted from the cell walls of soya bean cotyledons

  Harmen van Laar, Seerp Tamminga, Barbara A Williams, Martin W A Verstegen, Henk A Schols
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  ABSTRACT: Full-fat soya beans were separated into hulls and cotyledons. After separation the cell wall fraction was extracted from the cotyledons. These purified cell walls were sequentially extracted with 0.05 M cyclohexane-trans-1,2-diamine-N,N,N ′,N ′-tetraacetate (CDTA) + 0.05 M NH4 oxalate (extract 1), 0.05 M NaOH (extract 2), 1 M KOH (extract 3) and 4 M KOH (extract 4) to fractionate the cell wall into its polysaccharide fractions. The extraction procedure was designed to first extract the pectic fraction (extracts 1 and 2), after which more hemicellulose was extracted in subsequent steps (extracts 3 and 4). In addition to the polysaccharides solubilised during extraction, the residues after each extraction step were collected. Extracts and residues were analysed for their fermentation characteristics using an in vitro gas production procedure. Fermentability of the sequential extracts increased for each subsequent extraction step, as witnessed by an increasing rate of fermentation (from 2.2 to 10.0% h−1) and decreasing half-time of gas production (from 56.0 to 18.7 h). Fermentability of the residues increased after pectins had been removed in the first two extraction steps, as witnessed by a shorter half-time of gas production (from 47.0 to 29.7 h). Fermentability was similar for residues 2 and 3, but decreased again for residue 4, which was deemed to consist mainly of cellulose. The different cell wall sugars were degraded at different rates, with a rapid rate of degradation for galactose and arabinose, an intermediate rate for xylose and uronic acids and a slow rate for glucose. The sugar degradation rates for extract 1 had a similar ranking. These results are discussed in light of the concept that pectins determine the pore size of the cell wall matrix (Carpita NC and Gibeant DM, Planta J3: 1–30 (1993) and the model of the cell wall architecture of legumes of Hatfield (Hatfield RD, in Forage Cell Wall Structure and Digestibility, Ed by Jung HG, Buxton DR, Hatfield RD and Ralph J. American Society of Agronomy/Crop Science Society of America/Soil Science Society of America, Madison, WI, pp 285–313 (1993)).© 2000 Society of Chemical Industry
  Journal of the Science of Food and Agriculture 07/2000; 80(10):1477 - 1485. · 1.44 Impact Factor
• Article: Fermentation characteristics of polysaccharide fractions extracted from the cell walls of maize endosperm

  Harmen van Laar, Seerp Tamminga, Barbara Williams, Martin W A Verstegen, H. A. Schols
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  ABSTRACT: Cell walls were extracted from maize endosperm and separated into different polysaccharide fractions by sequential extraction with solutions of saturated Ba(OH)2, demineralised water and 1 and 4 M KOH. Solubilised polysaccharides were collected after each extraction. Residues were collected following the extractions with demineralised water and 1 and 4 M KOH. The original cell wall (CW) material, extracts and residues were analysed for their fermentation characteristics using an in vitro cumulative gas production technique. The rate of fermentation of the alkali-treated residues was faster than that of the original CW material, except for the 4 M KOH residue, which had a similar rate of degradation to the original CW material. The polysaccharides solubilised from the cell wall (extracts) were all rapidly fermented, more rapidly than both CW and residues. A division of the gas production profile into two phases using curve fitting was in good agreement with a division of the cell wall fermentation into the fermentation of arabinoxylans and cellulose. Therefore the likelihood of preferential degradation of arabinoxylans from the maize cell wall was discussed. The volatile fatty acid production pattern was fairly well explained by the fermentation rate and composition of the substrates. It was concluded that breaking the interactions of polysaccharides in the maize cell wall by mild alkali extraction increases the fermentability of maize cell walls in the gastrointestinal tract of farm animals. Contrarily, more severe alkali extractions will reduce the fermentability of maize cell walls. © 2002 Society of Chemical Industry