Dietary Reference Intakes Proposed Definition of Dietary Fiber (2001) / Chapter Skim
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Appendix C: Development and Evolution of Methods Used to Purify and Measure Dietary Fiber
Appendix C: Development and Evolution of Methods Used to Purify and Measure Dietary Fiber
Pages 49-62
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From page 49... ...
A correction is made for any remaining protein and ash, and the result is expressed as a proportion of the starting material. The enymatic-chemical approach chemically characterizes the carbohydrate content of fiber after the removal of available carbohydrate (monosaccharides, disaccharides, and starch)
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From page 50... ...
In the 1 970s, the use of the NDF method spread to human nutrition, but its utility remained limited because it did not include soluble fiber components nor did it remove all starch. With growing interest in dietary fiber in human nutrition in the 1970s and the development of a physiological role for this dietary component, Here was a need for an analytical method that measured insoluble cell wall and soluble fiber components.
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From page 51... ...
developed a method for "unavailable carbohydrates" which involved reflux with strong acid, followed by calorimetric determination of reducing sugars and pentoses. During the 1950s, Southgate continued to develop this chemical approach to fiber measurement, extending McCance and Lawrence's work by introducing a series of extraction steps followed by hydrolysis of polysaccharides and subsequent calorimetric analysis of component monosaccharides.
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From page 52... ...
The procedure does not remove resistant starch and measures lignin separately as Klason lignin, material insoluble in 72 percent sulfuric acid (Goering and Van Soest, 1970~. Originally, the method did not rely on ethanol precipitation of solubilized fiber components, but rawer recovered them from the soluble fraction by dialysis with a molecular weight cutoff of 12,000 to 14,000 daltons.
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From page 53... ...
, it is analyzed as a separate component, using the Klason lignin method (Goering and Van Soest, 1970~. This method measures native lignin, but can also include tannins, cutins, and Maillard reaction products (Theander et al., 1995~.
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From page 54... ...
Enzyrnatic-spectrophoto- Fructans metric Enzymati c-gravimetri c Enzymatic-gravimetric Enzymatic-grav imetric 54 DIETARY REFERENCE INTAKES TABLE4 Methods ofFiber Analysis Reference (Method) Procedure Type Measures Soluble dietary fiber Insoluble dietary fiber Total dietary fiber Polydextrose Total nonstarch polysaccharides Individual constituent sugars Soluble nonstarch polysaccharides, by difference Insoluble nonstarch polysaccharides Total n on starch pa lysacch arides Total dietary fiber including low molecular weight resistant maltodextrins Fructans Soluble dietary fiber Insoluble dietary fiber Total dietary fiber Total dietary fiber Soluble dietary fiber Insoluble dietary fiber Total dietary fiber Total dietary fiber Insoluble dietary fiber
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From page 55... ...
PROPOSED DEFINITION OFDIETARY FIBER 55 Total Dietary Fiber Determination Concerns Calculated as the weight of fiber residue less the weight of protein and ash or calculated as the sum of soluble and insoluble fiber Not applicable Calculated as the sum of the monosaccharides Sum of hexoses, pentoses, and uranic acids Calculated as the sum of insoluble fiber, high molecular weight and low molecular weight soluble fibers Not applicable Measured by independent analysis or calculated as the sum of soluble fiber and insoluble fiber Calculated as the weight of fiber residue less the weight of protein and ash Not applicable Calculated as the sum of the soluble and insoluble fiber Calculated as the weight of fiber residue less the weight of protein and ash Not applicable Does not estimate lignin Does not estimate lignin continued
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From page 56... ...
Quigley and Englyst' Enzymatic-high perform- Soluble nonstarch polysaccha 1992 ance liquid chroma- rides, by difference tographic insoluble nonstarch polysac charides Total nonstarch polysaccha rides Individual constituent sugars Schweizer and Wursch, 1979 Enzymatic-gravimetric Soluble dietary fiber Insoluble dietary fiber Total dietary fiber Southgate, 1969 Enymatic-colorimetric Soluble dietary fiber Insoluble dietary fiber Total dietary fiber Theander and Aman, Enzymatic-gas chroma- Insoluble neutral polysaccha 1979 tographic rides Soluble neutral polysaccha rides Theander and Wester lund, 1986 Uppsala Method of Theander et al., 1995 (AOAC 994.1 3) Insoluble uranic acids Soluble uranic acids Klason lignin Total dietary fiber Enzymatic-gas chromatographic Enymatic-gas chromatographic insoluble neutral polysaccharides Soluble neutral polysaccharides Insoluble uranic acids Soluble uranic acids Klason lignin Total dietary fiber Neutral polysaccharides Uronic acids Klason lignin Total dietaIy fiber .
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From page 57... ...
PROPOSED DEFINITION OF DIETARY FIBER 57 Total Dietary Fiber Determination Concerns Not applicable Calculated as the sum of the monosaccharides Calculated as the sum of soluble and insoluble fiber Sum of hexoses, pentoses, uranic acids, and lignin Calculated as the sum of neutral polysaccharides, uranic acids, and Klason lignin Calculated as the sum of neutral polysaccharides. uranic acids, and Klason lignin Calculated as the sum of neutral polysaccharide residues, uranic acid residues, and Klason lignin Does not estimate lignin Incomplete removal of starch, not specific with respect to individual sugars (Theander and Westerlund, 1986)
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From page 58... ...
Macromolecules are hydrolyzed as they become exposed, and hydrolytic products are rapidly absorbed. The successful analytical method for resistant starch will be one that mimics this process in the human gastrointestinal tract, so that the analytically determined value reflects starch not assimilated in the human.
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From page 59... ...
Because of the high polysaccharide content, these matenals may have physiological properties similar to dietary fiber. Some of these compounds are insoluble in 78 to 80 percent ethanol and therefore analyze as dietary fiber by all current dietary fiber methods.
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From page 60... ...
These have traditionally been considered dietary fiber and are captured in the existing dietary fiber methods. Other unabsorbable carbohydrates have been chemically synthesized or made resistant through physical or chemical modifications and include resistant starch, resistant maltodextrin, polydextrose, and hydroxymethylcellulose.
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From page 61... ...
Unmeant c~ohy~es did Dbe~l~e properties ma be mused de DOVO, modified' or Folded Tom existing fiber solaces far inco~o~ion in10 Mods or supplement Me challenge of de~ing dieted Bb~ is ~~ potential sores ~~ mu either meat chemical de0nkions or physiological editor requkemeD1s ~ expands ~ a ~ He ad chaDeDge Me exhale methods 10 determine fiber
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