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.
A determination of crude fiber is used in evaluation the efficiency of milling and separating bran from the starchy endosperm. Crude fiber is also useful in the chemical determination of succulence of fresh vegetables and fruits; over mature products have increased levels of crude fiber.
Today’s accepted term for fiber is dietary fiber, but this term has only been in use since late 1970s. Before that, the primitive term crude fiber was used because fiber was not considered important to health.
Recent research into the roles of dietary fiber components has caused reevaluation of some of the traditional concepts concerning fiber. Actually, dietary fiber may be an unfortunate misnomer; a term such as non-digestible portion may be correct since this dietary component may or may not have a fibrous structure.
The non-digestible or dietary fiber fraction is a complex mixture of different substance. The major ones are cellulose, the glucose polymer that is predominant material of plant cells; hemicellulose, a shorter version of cellulose: pectin, the glue that binds plant cells together with cellulose from the woody cell walls of plants.
Fiber offers a variety of health benefits and is essential in reducing the risk of chronic disease such as diabetes, obesity, cardiovascular disease and diverticulitis.
Dietary fiber acts to lower the concentration of low density lipoprotein cholesterol in the blood, possibly by binding with bile acids. The lignin fraction has been identified as the possible binding agent.
It is a known fact that fiber helps eliminate waste from the gastrointestinal tract because of its ability to bind water and thus soften the stool.
Crude Fiber
