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Fiber (Insoluble, Soluble, Total - Gravimetric) Test

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Fiber (Insoluble, Soluble, Total - Gravimetric) Test

Technical data sheet


Method description

Samples (defatted if necessary) are digested with three enzymes (alpha-amylase, protease and amyloglucosidase) to remove starch and protein. Any solid particles not in solution after digestion are considered insoluble dietary fiber and are filtered off and measured gravimetrically. The filtrate from this first filtration is collected and ethanol is added to precipitate the soluble dietary fiber. The soluble fraction is then filtered and measured gravimetrically. All residues are corrected for ash and protein content. Total dietary fiber is calculated as the sum of the insoluble and soluble percentages.

Acceptable matrices

All foods and food products

Unacceptable matrices



Standard Gravimetric Analytical Chemistry Equipment

Method reference

AOAC 991.43 with modifications

Reportable unit


Sample size requirements

40 grams

Information required by submitter

Please supply expected estimates. Indicate matrix type and indicate if samples are high in fat (>5%). Indicate whether the sample contains fructans (inulin or fructooligosaccharides (FOS)), or psyllium, flax and gum (i.e. guar gum).

Additional information

This test is ISO/IEC 17025 accredited through A2LA, Certificate # 2769.01.

Dietary Fiber is the portion of the carbohydrates which is not digested in the human gut. It is composed of both soluble and insoluble components. These methods are applicable to all food products, however samples containing psyllium or fructans should be submitted under specific test codes. High-fat (>5%) samples require special handling.

*Prices and offerings are subject to change without notice.

Common Fiber (Insoluble, Soluble, Total - Gravimetric) Test Testing Questions

While our sales and customer service team are happy to answer general testing questions, consultations typically start at a rate of $250 per 30 minutes regarding the interpretation of reported test results or questions about our test methods. We cannot consult on regulations, tolerance limits, or claims.

We make every effort to keep our methods and detection limits up to date according to the latest standards and qualifications. If you have any questions regarding the limit of detection/quantification or method references, please contact our Customer Service team at 1-800-245-5615.

Our standard turnaround time is 10 business days for most assays. There are some assays that require a longer turnaround time. We also offer a RUSH service that is half the time of the standard turnaround time of the assay at double the cost of the assay. A few assays that we provide cannot be rushed due to the nature of the test. Please check the specific assay you are interested in regarding the ability to RUSH the turnaround time.

Medallion Labs, a division of General Mills, offers multiple areas of expertise for analytical testing and product evaluation for the food and ingredient industry. Our areas of expertise include Chemical Analysis, Nutritional Analysis, Food Safety, Shelf Life Studies, Microbiology, Specialty Fibers, Physical Testing, Allergen Testing, as well as Product Evaluation (which includes Product Performance and Sensory Evaluation) and Technical Consulting/Method Development. Our methods are developed for the testing of food products and ingredients.

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Medallion Labs

A food testing program designed with mid-market and enterprise food and ingredient manufacturers in mind.