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

1997 ◽  
Vol 80 (1) ◽  
pp. 89-94 ◽  
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.

Determination of Total Dietary Fiber in Foods and Products with Little or No Starch, Nonenzymatic-Gravimetric Method: Collaborative Study

1994 ◽  
Vol 77 (3) ◽  
pp. 687-689 ◽  
Author(s):  
Betty W Li ◽  
Maria S Cardozo
Keyword(s):  
Standard Deviation ◽  
Dietary Fiber ◽  
Fruits And Vegetables ◽  
Simple Procedure ◽  
Collaborative Study ◽  
Gravimetric Method ◽  
Total Dietary Fiber ◽  
Freeze Dried ◽  
Relative Standard

Abstract A collaborative study was conducted to validate a nonenzymatic-gravimetric method for the determination of total dietary fiber (TDF) of samples containing little or no starch such as most fruits, and vegetables and many purified polysaccharides. This simple procedure involves suspension of freeze-dried, ground samples in deionized water and incubation at 37°C for 90 min, followed by pre-cipitation with 4 volumes of 95% ethanol. The weight of the dilute alcohol-insoluble residues after correcting for crude protein and ash corresponds to the TDF content of the sample. Six samples in blind duplicate (apples, apricots, cabbage, carrots, onions, and soy fiber) were sent with Celite to 10 laboratories. The reproducibility relative standard deviation (RSDr) of the TDF values for 9 laboratories ranged from 2.92 to 6.25%. The repeatability standard deviation (RSDr) for the 9 laboratories ranged from 1.50 to 2.70%. The method has been adopted first action by AOAC INTERNATIONAL.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

scholarly journals Crude Fat, Hexanes Extraction, in Feed, Cereal Grain, and Forage (Randall/Soxtec/Submersion Method): Collaborative Study

2003 ◽  
Vol 86 (5) ◽  
pp. 899-908 ◽  
Author(s):  
Nancy J Thiex ◽  
Shirley Anderson ◽  
Bryan Gildemeister ◽  
W Adcock ◽  
J Boedigheimer ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Animal Feed ◽  
Collaborative Study ◽  
Meat Products ◽  
The United States ◽  
Official Method ◽  
Cereal Grain ◽  
Relative Standard ◽  
Time Required

Abstract A method for determining crude fat in animal feed, cereal grain, and forage (plant tissue) was collaboratively studied. Crude fat was extracted from the animal feed, cereal grain, or forage material with hexanes by the Randall method, also called the Soxtec method or the submersion method. The use of hexanes provides for an alternative to diethyl ether for fat extractions. The proposed submersion method considerably decreases the extraction time required to complete a batch of samples compared to Soxhlet. The increase in throughput is very desirable in the quest for faster turnaround times and the greater efficiency in the use of labor. In addition, this method provides for reclamation of the solvent as a step of the method. The submersion method for fat extraction was previously studied for meat and meat products and was accepted as AOAC Official Method 991.36. Fourteen blind samples were sent to 14 collaborators in the United States, Sweden, Canada, and Germany. The within-laboratory relative standard deviation (repeatability) ranged from 1.23 to 5.80% for crude fat. Among-laboratory (including within) relative standard deviation (reproducibility) ranged from 1.88 to 14.1%. The method is recommended for Official First Action.

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

2007 ◽  
Vol 90 (1) ◽  
pp. 225-237 ◽  
Author(s):  
Kenichiro Kanaya ◽  
Shusaku Tada ◽  
Bunpei Mori ◽  
Rie Takahashi ◽  
Sachie Ikegami ◽  
...  
Keyword(s):  
Dietary Fiber ◽  
Enzymatic Digestion ◽  
Interlaboratory Study ◽  
Total Dietary Fiber ◽  
Stabilizing Agents ◽  
Modified Method ◽  
Relative Standard ◽  
Aoac Method ◽  
Standard Deviations

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.

scholarly journals Crude Fat, Diethyl Ether Extraction, in Feed, Cereal Grain, and Forage (Randall/Soxtec/Submersion Method): Collaborative Study

2003 ◽  
Vol 86 (5) ◽  
pp. 888-898 ◽  
Author(s):  
Nancy J Thiex ◽  
Shirley Anderson ◽  
Bryan Gildemeister ◽  
W Adcock ◽  
J Boedigheimer ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Diethyl Ether ◽  
Animal Feed ◽  
Collaborative Study ◽  
Meat Products ◽  
The United States ◽  
Official Method ◽  
Cereal Grain ◽  
Relative Standard

Abstract A method for determining crude fat in animal feed, cereal grain, and forage (plant tissue) was collaboratively studied. Crude fat was extracted from the animal feed, cereal grain, or forage material with diethyl ether by the Randall method, also called the Soxtec method or the submersion method. The proposed submersion method considerably decreases the extraction time required to complete a batch of samples. The increase in throughput is very desirable in the quest for faster turnaround times and the greater efficiency in the use of labor. In addition, this method provides for reclamation of the solvent as a step of the method. The submersion method for fat extraction was previously studied for meat and meat products and was accepted as AOAC Official Method 991.36. Fourteen blind samples were sent to 12 collaborators in the United States, Sweden, Canada, and Germany. The within-laboratory relative standard deviation (repeatability) ranged from 1.09 to 9.26% for crude fat. Among-laboratory (including within) relative standard deviation (reproducibility) ranged from 1.0 to 21.0%. The method is recommended for Official First Action.

scholarly journals Graphite Furnace Atomic Absorption Spectrometric Determination of Lead and Cadmium Extracted from Ceramic Foodware: Collaborative Study

2000 ◽  
Vol 83 (5) ◽  
pp. 1174-1188 ◽  
Author(s):  
Susan C Hight ◽  
N Ayyad ◽  
B Barnes ◽  
J Brown ◽  
B DePalma ◽  
...  
Keyword(s):  
Quality Control ◽  
Standard Deviation ◽  
Atomic Absorption ◽  
Graphite Furnace ◽  
Official Method ◽  
Lead And Cadmium ◽  
Modified Method ◽  
Relative Standard ◽  
Graphite Furnace Atomic Absorption ◽  
Atomic Absorption Spectrometric

Abstract A modification of the official flame atomic absorption spectrometric (FAAS) method for determining lead and cadmium extracted from ceramic foodware was collaboratively studied. In the modified method, graphite furnace atomic absorption spectrometry (GFAAS) is substituted for FAAS. The modified method also includes mandatory quality control procedures to improve method performance. The extraction procedure of the official method (leaching with 4% acetic acid for 24 h at room temperature) remains unchanged. Seven laboratories analyzed blind duplicate portions of 3 ceramicware leach solutions containing Pb at concentrations of 0.0196, 0.403, and 3.73 μg/mL and Cd at concentrations of 0.00236, 0.0456, and 0.544 μg/mL. Performance of the modified method compared well with that of the official method. The repeatability relative standard deviation (RSDr) ranged from 0.87 to 6.7% for Pb and from 3.7 to 11% for Cd. The reproducibility relative standard deviation (RSDR) ranged from 4.5 to 12% for Pb and from 7.0 to 11% for Cd. Accuracy of collaborator results was 97–98% for Pb and 93–101% for Cd. Quality control results and quantitation limits were excellent. Method quantitation limits varied among laboratories from 0.005 to 0.019 μg/mL for Pb and from 0.0004 to 0.0019 μg/mL for Cd. The modified method was adopted First Action by AOAC INTERNATIONAL.

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

2008 ◽  
Vol 91 (3) ◽  
pp. 614-621 ◽  
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.

scholarly journals Determination of Methylcellulose and Hydroxypropyl Methylcellulose Food Gums in Food and Food Products: Collaborative Study

2007 ◽  
Vol 90 (3) ◽  
pp. 786-793 ◽  
Author(s):  
Robert G Harfmann ◽  
Balasaheb K Deshmukh ◽  
Jerry Conklin ◽  
Maciej Turowski ◽  
Stephanie Lynch ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Hydroxypropyl Methylcellulose ◽  
Collaborative Study ◽  
Food Samples ◽  
Size Exclusion ◽  
Official Method ◽  
Relative Standard ◽  
Aoac Official

Abstract A collaborative study was performed to determine the reproducibility of a method for the determination of methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) in food. These widely used food gums possess unusual solubility characteristics and cannot accurately be determined by existing dietary fiber methods. The new method uses the enzyme-digestion procedure of AOAC Official Method 991.43. Digestate solutions must be refrigerated to fully hydrate MC or HPMC. The chilled solutions are filtered and analyzed by size-exclusion liquid chromatography. Collaborating laboratories received 28 samples containing MC or HPMC in the range of 0100%. The sample set included blind duplicates of 5 food matrixes (bread, milk, fish, potato, and powdered juice drink). Cochran and Grubbs tests were used to eliminate outliers. For food samples containing MC, values for within-laboratory precision, repeatability relative standard deviation (RSDr), ranged from 4.2 to 16%, and values for among-laboratories precision, reproducibility relative standard deviation (RSDR), ranged from 11 to 20%. For HPMC samples, RSDr values ranged from 6.4 to 27%, and RSDR values ranged from 17 to 39%. Recoveries of MC and HPMC from the food matrixes ranged from 78 to 101%. These results show acceptable precision and reproducibility for the determination of MC and HPMC, for which no Official AOAC Methods exist. It is recommended that this method be adopted as AOAC Official First Action.

scholarly journals Determination of Polydextrose as Dietary Fiber in Foods

2000 ◽  
Vol 83 (4) ◽  
pp. 1006-1012 ◽  
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.

scholarly journals Modification of Babcock Method to Eliminate Fat Testing Bias Between Babcock and Ether Extraction Methods (Modification of AOAC Official Methods 989.04 and 995.18): Collaborative Study

1997 ◽  
Vol 80 (4) ◽  
pp. 845-859 ◽  
Author(s):  
Joanna M Lynch ◽  
David M Barbano ◽  
J Richard Fleming
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Reference Method ◽  
Official Method ◽  
Test Results ◽  
Testing Bias ◽  
Ether Extraction ◽  
Relative Standard ◽  
Aoac Official ◽  
Aoac Official Method

Abstract The Babcock test for determining fat in milk (AOAC Official Method 989.04) and in cream (AOAC Official Method 995.18) gives consistently higher test results than does the modified Mojonnier ether extraction reference method (AOAC Official Methods 989.05 and 995.19). To decrease the density of material in Babcock columns and thus lower test results, the Babcock method was modified by lowering the temperatures used at various points in the method, from about 57.5° to 48°C. Using the AOAC collaborative study format, 9 laboratories tested 9 pairs of blind duplicate raw milk samples (fat range 2.5–5.7%) and 9 pairs of blind duplicate heat-treated cream samples (fat range 30–45%) using the temperature modified (TM) Babcock method. The ether extraction test was conducted as the reference method. The statistical performance (invalid and outlier data removed) of the TM Babcock method was, for milk: percent fat value of 4.110, repeatability standard deviation (sr) value of 0.037, reproducibility standard deviation (sR) value of 0.047, repeatability relative standard deviation (RSDr) value of 0.901% and reproducibility relative standard deviation (RSDR) value of 1.147%; and for cream: percent fat value of 37.555, sr value of 0.258, sR value of 0.353, RSDr value of 0.687% and RSDR value of 0.940%. The TM Babcock method performance was acceptable but not as good as that achieved in previous studies of the unmodified method. For the TM Babcock and ether methods, respectively, average percentages fat were 4.110 and 4.114 for milk, and 37.555 and 37.485 for cream. Temperature modification statistically eliminated the testing bias between methods. The tem-perature modifications of the Babcock methods for determination of fat in milk and cream (989.04 and 995.18) have been adopted revised first action by AOAC INTERNATIONAL.

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