Oxidative Gelation of Solvent-Accessible Arabinoxylans is the Predominant Consequence of Extensive Chlorination of Soft Wheat Flour
2009
Kweon, Meera | Slade, Louise | Levine, Harry
This study explores the effects of flour milling yield, extent of chlorination, and particle size on cake-flour functionality and potential batter viscosity using solvent retention capacity (SRC) testing and Bostwick flow. Straight-grade flour (SG, 74% milling yield) and low-extraction flour (Low X, 55% milling yield) samples were prepared from Croplan 594W (soft red winter wheat grown in Ohio in 2004). SRC tests were done according to Approved Method 56-11 (AACC International 2000). Flow distance was measured with a Bostwick consistometer, using a modification of the method of Bettge and Morris (2007). The moisture content of the postmilled sample was lower than those for the SG and Low X samples while the protein and ash contents of the SG sample were higher than those for the Low X and postmilled samples. Particle size distribution results for the samples clearly showed that the postmilled sample contained smaller flour particles. Results for the treatment without endoxylanase showed that the effects of the extent of chlorination on SRC and Bostwick flow were dramatic for all flour samples although milling yield and additional milling to reduce flour particle size were less significant factors. The most notable effect was observed for heavily chlorinated flours, for which sucrose SRC values increased markedly. The treatment with endoxylanase, on the other hand, resulted in increased Bostwick flow and decreased water and sucrose SRC values. The increased flow was greater for heavily chlorinated flours than for lightly chlorinated flours. This suggests a significant depolymerisation of oxidative gels. Most importantly, addition of hydrogen peroxide after incubation with endoxylanase caused no further change in Bostwick flow.
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