Cereal Chem. 70:152-157   |  VIEW ARTICLE

Assessment of Extrusion-Induced Starch Fragmentation by Gel-Permeation Chromatography and Methylation Analysis.

P. Rodis, L.-F. Wen, and B. P. Wasserman. Copyright 1993 by the American Association of Cereal Chemists, Inc. 

Three commercial corn starches (high-amylose, amylopectin-enriched, and corn meal) were extruded under various conditions and analyzed for changes in solubility, molecular size distribution, and linkage content. Each of the extruded starches dissolved in dimethyl sulfoxide at a faster rate than unprocessed material. Gel-permeation chromatography confirmed the occurrence of starch fragmentation. Methylation analysis showed only small changes in linkage distributions, suggesting that under the conditions tested, the total number of fragmentation points is small relative to the the total number of glycosidic linkages in starch. Furthermore, the absence of glucose or maltodextrins indicates that fragmentation sites are largely internal, rather than adjacent to the reducing or nonreducing termini of the amylopectin molecule.