The effects of different methods on the distribution of total neutral sugars (TNS), uronic acids (UA), and beta-glucans (beta G) between the soluble (S) and insoluble (I) fractions of dietary fiber (DF) were determined for peas, kidney beans, oat bran, rice, and macaroni. Incorporation of a protease step into the Theander method "A" modestly increased, and addition of a pepsin digestion further increased the proportion of total fiber recovered in the S fraction. The effect of extraction method on the distribution of TNS, UA, and beta G between the S and I fractions varied with the food. The three methods measured the same total DF in a food and 1-3% starch in the I fraction of peas and kidney beans. Use of dimethyl sulfoxide to solubilize starch, or elevated temperature to extract S components, had no effect on the distribution of DF between S and I fractions of peas and macaroni. Incomplete protein hydrolysis did not always lower Klason lignin and excluding lignin from the fiber complex did not always substantially increase the S fraction.
Compositions of neutral detergent fiber (NDF) residues and water insoluble fiber fractions extracted by the Southgate method from five foods were determined quantitatively and compared. Neutral saccharide compositions of the two fiber residues, measured by HPLC, were similar for four of the five foods. Uranic acids constituted 4 -8% of fiber in all foods. When adjustments were made for protein, starch and moisture contents, mean recovery of the two fibers was 97.9 f 3.9%. Gravimetric quantitation of NDF or of a Southgate-derived insoluble fiber usually yielded a fiber content similar to the chemically determined value, although each of the Southgate residues had to be corrected for starch and/or crude protein content.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.