Determination of crude fiber content
Principle
Fiber refers to the indigestible carbohydrate component that is present in plants. The
name is derived from the fact that it has a naturally fibrous structure. Its primary purpose in
plants is to form part of the structure in the cells, but it is also useful for the human diet. Crude
fiber is a little-used distinction to differentiate the types of fiber. Crude fiber is a measure of the
quantity of indigestible cellulose, pentosans, lignin, and other components of this type in present
foods. It is the residue of plant materials remaining after solvent extraction followed by digestion
with dilute acid and alkali. These components have little food value but provide the bulk
necessary for proper peristaltic action in the intestinal tract.