COMPARISON AND ASSESSMENT OF THE DIFFERENCE IN TOTAL DIETARY FIBER INCOOKED DRIED LEGUMES AS DETERMINED BY 5 METHODS

Dried beans (kidney and great northern) and dried peas (chick, green, and yellow) were cooked according to package instructions. Total dieta ry fiber (TDF) was measured by the Mongeau (AOAC 992.16), Prosky (AOAC 985.29), and Lee (AOAC 991.43) methods (A, B, and C, respectively). N onstarch polysaccharides (NSP) were measured by the Englyst gas-chroma tographic method that included dimethyl sulfoxide treatment, and the l ignin measured separately was added to NSP (method D). TDF was also me asured by the Li method (E). TDF values ranged from 7 to 48 g/100 g dr y weight. Methods B and C gave similar TDF values, which were higher t han those from other methods. For kidney beans I, TDF values by method s B and C were up to 2.5 times higher because of the inclusion of star ch. The fiber residues from methods A and C contained the same amounts of arabinose, xylose, mannose, galactose, and uronic acid, but glucos e was 4 times higher in residue C than in residue A. When alpha-amylas e from porcine pancreas was incorporated in methods B or C for 5 sampl es, the discrepancies among methods A, B, and C were reduced by 60-98% .