AOAC 991.43: Determination of Total Dietary Fiber

Dietary fiber is defined as a complex mixture of organic substances, including soluble and insoluble polysaccharides, and non-swelling, more or less hydrophobic compounds such as indigestible oligosaccharides, cutins, suberins, and lignins.

Eating a diet high in dietary fiber supports intestinal function, especially foods containing high dietary fiber are preferred for healthy nutrition. The total, soluble and insoluble dietary fiber content of a sample (TDF, SDF and IDF, respectively) is measured using a MES-Tris buffer with the AOAC 991.43 standard.

- The sample is degreased and dispersed in the buffer.
- Starch is gelatinized and partially digested by alpha-amylase.
- It is then digested again with protease and amyloglucosidase enzymes.
- The undigested mass of IDF is filtered off, dried and weighed.
- Ethanol is added to the filtrate to precipitate the SDF.
- The undigested SDF mass is isolated, dried and weighed.
- If TDF is desired directly without quantification of IDF and SDF, the IDF filtration step is skipped.

AOAC 991.43: Total, Soluble and Insoluble Dietary Fiber in Foods

You can contact Nanolab Food Analysis Laboratory for Determination of Total Dietary Fiber in Foods.