A Simplified Modification of the AOAC Official Method for Determination of Total Dietary Fiber Using Newly Developed Enzymes: Preliminary Interlaboratory Study

Abstract A preliminary interlaboratory study was conducted to evaluate the validity of the modified AOAC method for determination of total dietary fiber by Tada and Innami, in which the 3-step enzymatic digestion process in AOAC Method 991.43 is modified to a 2-step process without pH adjustment. Total dietary fiber contents in 8 representative foodstuffs were measured using both the original AOAC Method 991.43 and the modified method in 6 research facilities in Japan. Repeatability relative standard deviations, reproducibility relative standard deviations, and Horwitz ratio values from the modified method were equivalent to those from AOAC Method 991.43, except in the rice sample. However, this exceptional case shown in the modified method was entirely dissolved by the addition of α-amylase stabilizing agents. The modified method, which shortens the process of enzymatic digestion from 3 to 2 steps and in which only reaction temperature is adjusted under the same pH, was found not only to give accurate values comparable to the original method, but also to substantially reduce the labor required by the laboratory staff in the process of routine analysis. This study revealed that the validity of the modified method was further ensured by adding α-amylase stabilizing agents to the reaction system.

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Determination of Total Dietary Fiber in Foods and Food Products by Using a Single-Enzyme, Enzymatic-Gravimetric Method: Interlaboratory Study

Journal of AOAC International ◽

10.1093/jaoac/78.6.1440 ◽

1995 ◽

Vol 78 (6) ◽

pp. 1440-1443

Author(s):

Betty W Li

Keyword(s):

Dietary Fiber ◽

Gravimetric Method ◽

Food Composition ◽

Interlaboratory Study ◽

Department Of Agriculture ◽

Total Dietary Fiber ◽

Relative Standard ◽

Simplified Method ◽

Standard Deviations

Abstract A simplified enzymatic-gravimetric method for total dietary fiber (TDF) determination has been published and used in the Food Composition Laboratory of the U.S. Department of Agriculture since 1988. This method gives comparable results to AOAC Official Methods 985.29 and 991.43 but the AOAC methods use 100°C (water bath) to gelatinize the sample and a combination of α-amylase and an amyloglucosidase to hydrolyze starches, whereas the simplified method incorporates an autoclaving step (121°C) for gelatinization followed by incubation with only amyloglucosidase. The simplified method omits protease hydrolysis and does not require any pH adjustment. Overall, the simplified method cuts cost and is less labor intensive. An interlaboratory study was conducted to validate this method. Blind duplicates of six sample (baked beans, corn bran, roasted peanuts, cooked potatoes, white bread with reduced calories, and cooked white rice) were sent to 11 laboratories. The reproducibility relative standard deviations of the TDF values (without outliers) ranged from 3.46 to 27.6%. The repeatability standard deviations ranged from 0.91 to 14.6%.

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A Simplified Modification of the AOAC Official Method for Determination of Total Dietary Fiber Using Newly Developed Enzymes

Journal of AOAC International ◽

10.1093/jaoac/90.1.217 ◽

2007 ◽

Vol 90 (1) ◽

pp. 217-224 ◽

Cited By ~ 3

Author(s):

Shusaku Tada ◽

Satoshi Innami

Keyword(s):

Dietary Fiber ◽

Corn Starch ◽

Enzymatic Digestion ◽

Soluble Starch ◽

Wheat Starch ◽

Official Method ◽

Total Dietary Fiber ◽

Modified Method ◽

Aoac Method

Abstract Since 1985, AOAC Method 985.29 has been globally adopted as a standard method for determination of total dietary fiber in foods. Nevertheless, an aspect of AOAC Method 985.29 that needs to be improved is the laborious process to treat 3 enzymes separately at their individual proper pH, which is quite time-consuming. Several examinations have been carried out to resolve this problem. The characteristics of newly developed thermostable -amylase, neutral protease, and amyloglucosidase were evaluated based on the pH-activity profile and the property of starch hydrolysis in comparison with those of the conventional enzyme reagents. These 3 developed enzymes were found to work under the same pH condition and to accomplish sufficient digestion for the typical 3 starches: soluble starch, corn starch, and wheat starch. The experimental results revealed that the dietary fiber determination in foods could be performed without pH adjustment in the enzymatic digestion process. The modified method will be greatly helpful in determining the total dietary fiber contents in food materials with less laborious work and with an accuracy equivalent to that of AOAC Method 985.29.

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Determination of Total Dietary Fiber in Selected Foods Containing Resistant Maltodextrin by a Simplified Enzymatic-Gravimetric Method and Liquid Chromatography: Interlaboratory Study in China

Journal of AOAC International ◽

10.1093/jaoac/91.3.614 ◽

2008 ◽

Vol 91 (3) ◽

pp. 614-621 ◽

Cited By ~ 2

Author(s):

Boqiang Fu ◽

Jing Wang ◽

Jean Michel Roturier ◽

Zhiyu Tang ◽

Huan Li ◽

...

Keyword(s):

Dietary Fiber ◽

Interlaboratory Study ◽

National Standard ◽

Official Method ◽

Total Dietary Fiber ◽

Modified Method ◽

Resistant Maltodextrin ◽

Aoac Official ◽

Aoac Official Method

Abstract An interlaboratory study was conducted in China to validate the modified AOAC Official Method 2001.03 for the determination of total dietary fiber (TDF) in foods containing resistant maltodextrin (RMD), which will be adopted as the National Standard Method of China. The kind of buffer solution, the volume of filtrate evaporation, the volume of eluent for desalting and residual solution after evaporation, etc. were modified, which had been proved to have acceptable accuracy and precision in the routine assay. TDF contents in 3 representative foods and 2 kinds of RMD ingredient (i.e., NUTRIOSE 06 and NUTRIOSE 10) were measured using the modified method in 6 eligible laboratories representing commercial, industrial, and governmental laboratories in China. The results of the interlaboratory study indicated that the intralaboratory repeatability, interlaboratory reproducibility, and precision of the modified method are adequate for reliable analysis of TDF in food containing RMD, as well as resistant dextrin. Compared to AOAC Official Method 2001.03, the modified method is time- and cost-saving.

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Determination of Total Dietary Fiber (CODEX Definition) by Enzymatic-Gravimetric Method and Liquid Chromatography: Collaborative Study

Journal of AOAC International ◽

10.1093/jaoac/93.1.221 ◽

2010 ◽

Vol 93 (1) ◽

pp. 221-233 ◽

Cited By ~ 83

Author(s):

Barry V McCleary ◽

Jonathan W De Vries ◽

Jeanne I Rader ◽

Gerald Cohen ◽

Leon Prosky ◽

...

Keyword(s):

Molecular Weight ◽

Dietary Fiber ◽

Resistant Starch ◽

Collaborative Study ◽

Gravimetric Method ◽

Low Molecular Weight ◽

Total Dietary Fiber ◽

Aoac Method ◽

Standard Deviations

Abstract A method for the determination of total dietary fiber (TDF), as defined by the CODEX Alimentarius, was validated in foods. Based upon the principles of AOAC Official MethodsSM 985.29, 991.43, 2001.03, and 2002.02, the method quantitates high- and low-molecular-weight dietary fiber (HMWDF and LMWDF, respectively). In 2007, McCleary described a method of extended enzymatic digestion at 37C to simulate human intestinal digestion followed by gravimetric isolation and quantitation of HMWDF and the use of LC to quantitate low-molecular-weight soluble dietary fiber (LMWSDF). The method thus quantitates the complete range of dietary fiber components from resistant starch (by utilizing the digestion conditions of AOAC Method 2002.02) to digestion resistant oligosaccharides (by incorporating the deionization and LC procedures of AOAC Method 2001.03). The method was evaluated through an AOAC collaborative study. Eighteen laboratories participated with 16 laboratories returning valid assay data for 16 test portions (eight blind duplicates) consisting of samples with a range of traditional dietary fiber, resistant starch, and nondigestible oligosaccharides. The dietary fiber content of the eight test pairs ranged from 11.57 to 47.83. Digestion of samples under the conditions of AOAC Method 2002.02 followed by the isolation and gravimetric procedures of AOAC Methods 985.29 and 991.43 results in quantitation of HMWDF. The filtrate from the quantitation of HMWDF is concentrated, deionized, concentrated again, and analyzed by LC to determine the LMWSDF, i.e., all nondigestible oligosaccharides of degree of polymerization 3. TDF is calculated as the sum of HMWDF and LMWSDF. Repeatability standard deviations (sr) ranged from 0.41 to 1.43, and reproducibility standard deviations (sR) ranged from 1.18 to 5.44. These results are comparable to other official dietary fiber methods, and the method is recommended for adoption as Official First Action.

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Determination of Total Dietary Fiber in Japanese Foods

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/74.2.350 ◽

1991 ◽

Vol 74 (2) ◽

pp. 350-359 ◽

Cited By ~ 2

Author(s):

Takahiro Nishimune ◽

Tatsuo Sumimoto ◽

Tsumoru Yakusiji ◽

Nobuharu Kunita ◽

Tomio Ichikawa ◽

...

Keyword(s):

Dietary Fiber ◽

Colorimetric Method ◽

Total Dietary Fiber ◽

Relative Standard ◽

Kjeldahl Method ◽

Aoac Method ◽

Fiber Components ◽

Unsuitable Samples ◽

Fiber Sample

Abstract Total dietary fiber was determined In Japanese foods by the Prosky-AOAC method. To accomplish the analyses of unsuitable samples, we Introduced a few minor modifications to the versions for (I) seaweed and fruits, (II) cereals, and (ill) fish and meats. These modified methods were used together with the standard method to obtain results with reasonably good relative standard deviation for 231 foods and 21 groups of mixed foods. In this study, dietary fiber was defined so as not to exclude the nondlgestlble polysaccharide portions of animal foods. A method was proposed which could estimate more accurately the fiber components of animal foods by measuring the "nondlgestlble protein" of the fiber sample by the Biuret colorimetric method, Instead of the Kjeldahl method, to avoid deducting the values for aminopolysaccharides. In Japanese diets, the amount of fiber obtained from animal foods was less than 5 % of the total Intake of dietary fiber.

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Fine Tuning a Bile-Enzymatic-Gravimetric Total Dietary Fiber Method

Journal of AOAC International ◽

10.1093/jaoac/80.1.89 ◽

1997 ◽

Vol 80 (1) ◽

pp. 89-94 ◽

Cited By ~ 1

Author(s):

Kenneth J Cranker ◽

Katherine M Phillips ◽

Maria Carmen Rita V Gonzales ◽

Kent K Stewart

Keyword(s):

Standard Deviation ◽

Dietary Fiber ◽

Collaborative Study ◽

Original Method ◽

Fine Tuning ◽

Official Method ◽

Total Dietary Fiber ◽

Modified Method ◽

Relative Standard ◽

Wet Weight

Abstract A recently proposed bile-enzymatic-gravimetric total dietary fiber (TDF) method was modified and the new procedure was compared with the original method, the traditional AOAC enzymatic-gravimetric determination (AOAC Official Method 985.29), and another simplified AOAC procedure by analyzing several diet composites, including National Institute of Standards and Technology 1548 total diet reference material. The original and modified bile-enzymatic-gravimetric procedures also were compared by analyzing 9 food samples from a collaborative study of the original method. The modified method consistently yielded values about 10% lower than the original method but closer to reference values and to values from AOAC Offical Method 985.29, suggesting results that are more in line with accepted TDF standard methodology. Our modified method was used to analyze 180 fresh-frozen diet composites with TDF values ranging from 0.6 to 3.2 g/100 g wet weight. Samples were from 2 multicenter feeding studies sponsored by the National Heart, Lung and Blood Institute: DELTA (Dietary Effects on Lipoproteins and Thrombogenic Activity) and DASH (Dietary Approaches to Stop Hypertension). The mean relative standard deviation (RSD) for duplicate analyses was 1.1%. For 40 assays of a quality control diet composite over 9 months, the standard deviation was 0.1 g/100 g wet weight (4.9% RSD), indicating the method’s excellent precision for routine use.

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Urea Enzymatic Dialysis Procedure for Determination of Total Dietary Fiber

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/72.4.677 ◽

1989 ◽

Vol 72 (4) ◽

pp. 677-681

Author(s):

Joseph L Jeraci ◽

Betty A Lewis ◽

J Peter ◽

Van J Soest ◽

James B Robertson

Keyword(s):

Dietary Fiber ◽

Crude Protein ◽

Gravimetric Method ◽

New Method ◽

Locust Bean Gum ◽

Total Dietary Fiber ◽

Insoluble Dietary Fiber ◽

Aoac Method ◽

Locust Bean

Abstract A method that uses urea and enzymes for determination of total dietary fiber (TDF) in foods has been developed and compared with the AOAC enzymatic-gravimetric method (43.A14-43.A20). In the evaluation, results for crude protein and ash contamination were higher by the AOAC method, particularly for samples that form gels during ethanol precipitation. The new urea enzymatic dialysis (UED) method quantitatively recovered, with less variation, more of the purified and semipurified dietary fiber products. TDF recoveries for carboxymethylcellulose and locust bean gum were 98% (SD 3.3) and 95% (SD 6.1) by the AOAC method and 99% (SD 1.0) and 100% (SD 0.6) by the UED method, respectively. The UED method was the more effective in removing starch. For kale samples, starch recovery was 3.5 and 0.2% from TDF residues obtained using the AOAC and UED methods, respectively. Differences were not significant among replicate values for determination of TDF in foods by the UED method (P >0.01). Preliminary studies suggest that the new method can separately determine soluble and insoluble dietary fiber. The data indicate that the UED method is more precise and accurate than the AOAC method.

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Determination of Polydextrose as Dietary Fiber in Foods

Journal of AOAC International ◽

10.1093/jaoac/83.4.1006 ◽

2000 ◽

Vol 83 (4) ◽

pp. 1006-1012 ◽

Cited By ~ 18

Author(s):

Stuart A S Craig ◽

James F Holden ◽

Maha Y Khaled

Keyword(s):

Standard Deviation ◽

Dietary Fiber ◽

Anion Exchange Chromatography ◽

Exchange Chromatography ◽

Physiological Effects ◽

Total Dietary Fiber ◽

Internal Validation ◽

Relative Standard ◽

Centrifugal Ultrafiltration

Abstract Polydextrose (Litesse®) provides physiological effects consistent with dietary fiber. However, AOAC methods for measuring total dietary fiber (TDF) in foods include an ethanol precipitation step in which polydextrose and similar carbohydrates are discarded and therefore not quantitated. This study describes a method developed to quantitate polydextrose in foods. The new method includes water extraction, centrifugal ultrafiltration, multienzyme hydrolysis, and anion exchange chromatography with electrochemical detection. Six foods were prepared with 4 levels of polydextrose to test the ruggedness of the method. Internal validation demonstrated the ruggedness of the method with recoveries ranging from 83 to 104% with an average of 95% (n = 24) and relative standard deviation of recoveries ranging from 0.7 to 13% with an average of 3.3% (n = 24). The value is added to that obtained for dietary fiber content of foods using the AOAC methods, to determine the TDF content of the food.

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Determination of Cry9C Protein in Corn-Based Foods by Enzyme-Linked Immunosorbent Assay: Interlaboratory Study

Journal of AOAC International ◽

10.1093/jaoac/84.6.1891 ◽

2001 ◽

Vol 84 (6) ◽

pp. 1891-1902 ◽

Cited By ~ 5

Author(s):

Mary W Trucksess ◽

T Artis ◽

C Diaz ◽

C Fernandez ◽

K Harkin ◽

...

Keyword(s):

Immunosorbent Assay ◽

Specific Interaction ◽

Strong Acid ◽

The United States ◽

Interlaboratory Study ◽

Enzyme Linked Immunosorbent Assay ◽

Corn Flour ◽

Relative Standard ◽

Standard Deviations

Abstract The performance of a commercially available enzyme-linked immunosorbent assay kit (Enviro-Logix) was assessed for the determination of Cry9C protein, which is produced by the genetically modified corn StarLink, in 8 types of corn-based foods (starch, refined oil, soft tortillas, tortilla chips, corn flakes, corn puffs, corn muffins, and corn bread) in an interlaboratory study involving 7 laboratories in the United States. The assay kit is a double antibody sandwich and is based on the specific interaction between antibody and antigen. The Cry9C protein analyte is sandwiched between 2 antibodies, one to capture the analyte and the other is conjugated to the enzyme, horseradish peroxidase. The enzyme uses tetramethylbenzidine/peroxide for color development. A strong acid stopping reagent is then used to change the color from blue to a stable yellow. The intensity of the color is proportional to the concentration of the Cry9C protein. In this study blind duplicates of control samples (blank material prepared from non- StarLink corn), spiked samples (blank material with the addition of Cry9C protein), and samples containing incurred analyte (products prepared with StarLink corn) were analyzed. Cry9C protein from 2 different sources was used to spike the food products. Cry9C protein produced and purified from a bacterial host was used to prepare spiked test samples at 2.72 and 6.8 ng/g. Cry9C protein from StarLink corn flour was used to prepare spiked samples at 1.97 ng/g. Average recoveries for samples spiked with corn flour Cry9C protein at 1.97 ng/g ranged from 73 to 122%, within-laboratory relative standard deviations (RSDr) ranged from 6 to 22%, and between-laboratories relative standard deviations (RSDR) ranged from 16 to 56%. Average recoveries for samples spiked with bacterial Cry9C protein at 2.72 and 6.8 ng/g ranged from 27 to 96% and from 32 to 113%, respectively; RSDr values ranged from 10 to 35%and from 7 to 38%, respectively; and the RSDR ranged from 28 to 84%and 15 to 75%, respectively. The incurred test samples were found to contain Cry9C protein at levels ranging from 0.8 to 3187 ng/g depending on the product, RSDr values ranged from 5 to 16% and RSDR values ranged from 11 to 71%. Results of the statistical analysis indicate that this method is applicable to the determination of Cry9C protein in the 8 types of collaboratively studied corn-based products containing Cry9C protein (from StarLink ) at levels of ≥2 ng/g.

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Determination of Total Dietary Fiber in Selected Foods Containing Resistant Maltodextrin by Enzymatic-Gravimetric Method and Liquid Chromatography: Collaborative Study

Journal of AOAC International ◽

10.1093/jaoac/85.2.435 ◽

2002 ◽

Vol 85 (2) ◽

pp. 435-444 ◽

Cited By ~ 34

Author(s):

Dennis T Gordon ◽

Kazuhiro Okuma ◽

J W DeVries ◽

K Fukuhara ◽

W Jacob ◽

...

Keyword(s):

Liquid Chromatography ◽

Dietary Fiber ◽

Average Molecular Weight ◽

Collaborative Study ◽

Gravimetric Method ◽

Soluble Dietary Fiber ◽

Total Dietary Fiber ◽

Resistant Maltodextrin ◽

Standard Deviations

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.

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