Publication no. C-1997-0815-03R |  VIEW ARTICLE

NOTE: Water Solubility and Macromolecular Properties of Corn Meal Extrudates as Affected by Epichlorohydrin (1).

Masahiro Kojima (2,3), Milford A. Hanna (2,4), and Aristippos Gennadios (2,5). (1) Journal Series 11618, Agricultural Research Division, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln. (2) Visiting researcher, director, and postdoctoral research associate, respectively, Industrial Agricultural Products Center, University of Nebraska, Lincoln, NE 68583-0730. (3) Presently with Food Research Institute, Aichi Prefectural Government, Japan. (4) Corresponding author. E-mail: <bsen024@unlvm.unl.edu> (5) Presently research scientist, Banner Pharmacaps, Inc., 4125 Premier Drive, High Point, NC, and adjunct assistant professor, Department of Biological Systems Engineering, University of Nebraska, Lincoln, NE 68583-0726. Cereal Chem. 74(5):526-529. Accepted April 12, 1997. Copyright 1997 by the American Association of Cereal Chemists, Inc.

Degermed corn meal adjusted to 18% moisture content (db) with epichlorohydrin (ECH) content at 0, 0.5, 1, or 2% (w/w) were extruded with a twin-screw laboratory extruder at a screw speed of 140 rpm. Compression and metering barrel zones were set at 100, 120, or 140°C. Water solubility (WS) of ground extrudates ranged from 7.6 ± 1.1% to 14.3 ± 1.3%. ECH content had a significant (P < 0.01) negative effect on WS, while barrel temperature and the interaction between barrel temperature and ECH content were not significant (P > 0.05). Presumably, ECH reduced WS of extrudates through cross-linking between hydroxyl groups on starch and protein molecules. Gel-permeation chromatography patterns for both 100 and 140°C barrel temperatures showed that high molecular weight carbohydrates in the extrudates decreased with increasing ECH content without a simultaneous increase in low molecular weight carbohydrates. This suggested that the decrease in high molecular weight fractions was due to insolubilization by cross-linking rather than degradation. SDS-PAGE revealed that two protein bands of approximately 29 and 17.5 kDa disappeared, and a new band appeared at 45 kDa with increasing ECH content. This indicated that, most likely, ECH reacted with protein in addition to reacting with starch. However, glycoprotein and starch-protein complexes were not identified with electrophoresis.