Cereal Chem 61:14 - 19.  |  VIEW ARTICLE
Dietary Fiber Content and Composition in Six Cereals at Different Extraction Rates.

M. Nyman, M. Siljestrom, B. Pedersen, K. E. Bach Knudsen, N.-G. Asp, C.-G. Johansson, and B. O. Eggum. Copyright 1984 by the American Association of Cereal Chemists, Inc. 

An enzymatic method was used to examine the relationship between extraction rate and dietary-fiber content in flours from wheat, rye, barley, sorghum, rice, and corn. Results were compared with neutral- detergent, acid-detergent, and crude-fiber determinations. Dietary-fiber content in wheat was constant for extraction rates between 65 and 80%, and then increased linearly with the extraction rate. Dietary fiber content in rice and to some extent in barley had a similar relationship, whereas in rye and sorghum it increased gradually with the extraction rate. Soluble dietary-fiber content was constant in each cereal, regardless of the extraction rate, and constituted almost half of the dietary fiber in wheat, rye, and barley flours of low extraction rate. The relative monomeric compostion of the dietary fiber in wheat, rye, and corn was similar at the highest and the lowest rates of extractions, with xylose-arabinose ratios being 0.9-1.5. In barley and rice, the relative xylose content increased with the rate of extraction, whereas in sorghum, both arabinose and xylose content increased. Acid-detergent and crude fiber comprised only a fraction of insoluble and of total dietary fiber. The slope of the regression equation between insoluble dietary fiber and neutral-detergent fiber amylase was 0.8-1.0 for wheat, rye, barley, and rice and 1.2 for corn. Detergent methods applied to sorghum gave obscure results.