Fiber, Total, Soluble and Insoluble (Gravimetric)

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Price of the test:

$208 per analysis

Acceptable Matrices:

All foods and food products

Limit of Detection:

Total Dietary Fiber - 0.1%
Insoluble Fiber – 0.1%
Soluble Dietary Fiber-0.1%

Sample Size Requirements:

40 grams


Standard Gravimetric Analytical Chemistry Equipment

Reportable Units:

Percent by weight of sample as received

Turn Around Time:

15 Business Days (Standard Turnaround)
7 Business Days (Rush Turnaround)

Is Rush Available?


Method Reference:

AOAC 991.43 with modifications

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.

Information Required by Submitter:

Please supply expected estimates. Indicate matrix type and indicate high fat (>5%) and high protein (>20%) samples. 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%) and high-protein (>20%, depending on matrix) samples require special handling.