International Survey on Dietary Fiber: Definition, Analysis, and Reference Materials

1995 ◽  
Vol 78 (1) ◽  
pp. 22-36 ◽  
Author(s):  
Sungsoo C Lee ◽  
Leon Prosky

Abstract An international survey was conducted to get the views of 147 professionals in the field on the definition of dietary fiber. The survey also solicited opinions on analytical methods for nutrition labeling, quality control, and nutrition research. The survey finds that dietary fiber is generally defined as polysaccharides and lignin that are not hydrolyzed by human alimentary enzymes. Support is strong for expansion of the definition to include oligosaccharides that are resistant to hydrolysis by human alimentary enzymes. Among techniques for nutrition labeling and quality control, enzymatic-gravimetric methods get the highest support. For nutrition research, more detailed methods such as gas-liquid chromatography and liquid chromatography were considered more appropriate. Respondents support labeling of total, soluble, and insoluble dietary fiber or total dietary fiber alone as sufficient for nutrition labeling of food packages. However, for nutrition research, detailed analytical methods, improvements in accuracy (i.e., closer simulation of in vitro techniques to conditions of human gastrointestinal tract), and improvements in precision and simplicity are suggested. Less than 20% of the participants use reference materials for dietary fiber analysis.

2004 ◽  
Vol 87 (1) ◽  
pp. 162-165 ◽  
Author(s):  
Leila G Saldanha ◽  
Joseph M Betz ◽  
Paul M Coates

Abstract The need for validated analytical methods and reference materials to identify and measure constituents in dietary supplements is essential. Such methods allow for the documentation that products meet manufacturer's specifications and contain what their labels declare. In March 2003, the U.S. Food and Drug Administration issued a proposed rule that would establish specific current good manufacturing practices for dietary supplements. This proposed rule requires that companies create a quality control unit to set specifications and ensure compliance with these specifications using scientifically valid procedures. This report provides insights and lessons learned from 3 meetings the Office of Dietary Supplements (ODS) at the National Institutes of Health helped organize. These meetings were structured to (1) educate individuals about the importance and need for validated analytical methods and reference materials to identify and quantify constituents of dietary supplements; (2) identify resources required to fulfill this need; and (3) serve as a platform to obtain input from interested parties to help frame the research agenda for the Dietary Supplements Methods and Reference Materials Program within ODS. Stakeholder's opinions and views expressed at these 3 meetings are outlined in this report.


2002 ◽  
Vol 85 (2) ◽  
pp. 435-444 ◽  
Author(s):  
Dennis T Gordon ◽  
Kazuhiro Okuma ◽  
J W DeVries ◽  
K Fukuhara ◽  
W Jacob ◽  
...  

Abstract A method was developed for determination of total dietary fiber (TDF) in foods containing resistant maltodextrin (RMD) which includes nondigestible carbohydrates that are not fully recovered as dietary fiber by conventional TDF methods such as AOAC 985.29 or 991.43. Because the average molecular weight (MW) of RMD is 2000 daltons, lower MW soluble dietary fiber components do not precipitate in 78% ethanol; therefore, RMD is not completely quantitated as dietary fiber by current AOAC methods. The accuracy and precision of the method was evaluated through an AOAC collaborative study. Ten laboratories participated and assayed 12 test portions (6 blind duplicates) containing RMD. The 6 test pairs ranged from 1.5 to 100% RMD. The method consisted of the following steps: (1) The insoluble dietary fiber (IDF) and high MW soluble dietary fiber (HMWSDF) were determined by AOAC 985.29. (2) Ion exchange resins were used to remove salts and proteins contained in the AOAC 985.29 filtrates (including ethanol and acetone). (3) The amount of low MWRMD (LMWRMD) in the filtrates were determined by liquid chromatography. (4) The TDF was calculated by summation of the IDF, HMWSDF, and LMWRMD fractions having nondigestible carbohydrates with a degree of polymerization of 3 and higher. Repeatability standard deviations (RSDr) were 1.33–7.46%, calculated by including outliers, and 1.33–6.10%, calculated by not including outliers. Reproducibility standard deviations (RSDR) were 2.48–9.39%, calculated by including outliers, and 1.79–9.39%, calculated by not including outliers. This method is recommended for adoption as Official First Action.


2019 ◽  
Vol 102 (1) ◽  
pp. 52-62 ◽  
Author(s):  
George C Fahey ◽  
Lawrence Novotny ◽  
Brian Layton ◽  
David R Mertens

Abstract Background: Because of its chemical complexity, the estimation of dietary fiber content of feed and food materials is a difficult analytical challenge. Three major fiber analyses are conducted routinely in the United States including crude fiber (CF), detergent fiber, and total dietary fiber (TDF). Objective: Factors crucial to the successful measurement of dietary fibers are described and suggestions provided as to how to overcome potential analytical problems within assays. Methods: An accounting of methodological details that result in variation in fiber concentration values is presented along with suggestions as to how to decrease the variation. Results: CF analysis remains in use in the livestock feed and pet food industries for nutrition labeling purposes in spite of the fact that the analysis does not separate mammalian enzyme-digestible from indigestible carbohydrate components, and values obtained are usually 30–50% of the actual dietary fiber concentration. Detergent fiber methods quantify the insoluble dietary fibers (IDF) accurately, but not the soluble dietary fiber (SDF) components. TDF methods account for intrinsic and intact fibers, isolated and extracted fibers, and synthetic fibers found in feed and food ingredients and complete diet matrixes. Conclusions: The CF procedure should be abandoned as it fails to quantify fiber properly. Detergent analyses quantify IDF. TDF methods quantify both IDF and SDF. Highlights: Accurate dietary fiber quantification is essential given the role of fiber in health and well-being of animals and humans.


1960 ◽  
Vol 38 (7) ◽  
pp. 1063-1069 ◽  
Author(s):  
T. Vrbaski ◽  
R. J. Cvetanović

A broad comparative survey has been made of the products of the vapor phase reactions of ozone with ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, isobutene, 2-methyl-1-butene, cis-2-butene, trans-2-butene, cis-2-pentene, trans-2-pentene, trimethyl ethylene, tetramethyl ethylene, cyclohexene, and 1,3-butadiene as determined by gas–liquid chromatography and, to a smaller extent, by other analytical methods.


2000 ◽  
Vol 83 (2) ◽  
pp. 413-424 ◽  
Author(s):  
Katherine E Sharpless ◽  
Lisa M Gill

Abstract A number of food-matrix reference materials (RMs) are available from the National Institute of Standards and Technology (NIST) and from Agriculture Canada through NIST. Most of these materials were originally value-assigned for their elemental composition (major, minor, and trace elements), but no additional nutritional information was provided. Two of the materials were certified for selected organic constituents. Ten of these materials (Standard Reference Material® [SRM] 1563 Cholesterol and Fat-Soluble Vitamins in Coconut Oil [Natural and Fortified], SRM 1566b Oyster Tissue, SRM 1570a Spinach Leaves, SRM 1974a Organics in Mussel Tissue (Mytilus edulis), RM 8415 Whole Egg Powder, RM 8418 Wheat Gluten, RM 8432 Corn Starch, RM 8433 Corn Bran, RM 8435 Whole Milk Powder, and RM 8436 Durum Wheat Flour) were recently distributed by NIST to 4 laboratories with expertise in food analysis for the measurement of proximates (solids, fat, protein, etc.), calories, and total dietary fiber, as appropriate. SRM 1846 Infant Formula was distributed as a quality control sample for the proximates and for analysis for individual fatty acids. Two of the materials (Whole Egg Powder and Whole Milk Powder) were distributed in an earlier interlaboratory comparison exercise in which they were analyzed for several vitamins. Value assignment of analyte concentrations in these 11 SRMs and RMs, based on analyses by the collaborating laboratories, is described in this paper. These materials are intended primarily for validation of analytical methods for the measurement of nutrients in foods of similar composition (based on AOAC INTERNATIONAL's fat–protein–carbohydrate triangle). They may also be used as “primary control materials” in the value assignment of in-house control materials of similar composition. The addition of proximate information for 10 existing reference materials means that RMs are now available from NIST with assigned values for proximates in 6 of the 9 sectors of the AOAC triangle. Five of these materials have values assigned for total dietary fiber—the first such information provided for materials available from NIST.


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