Variables Affecting the Determination of Crude Fiber

Abstract

The effects of time, concentration, and volume on determination of crude fiber have been studied on 12 materials. Results for crude protein and lignin content of crude fiber residues, determined by use of an acid detergent solution, hexadecyltrimethylammonium bromide, were compared with the AOAC crude fiber method. Variation in volume does not affect crude fiber. Most of the acid and soda digestion occurs in the first 15 minutes; thereafter solubilization is slow. Small variations in concentration have little effect on the results obtained. Precision in crude fiber determination demands rigid adherence to procedural details. Crude fiber contains some residual crude proteins and approximately onehalf of the original lignins. Crude fiber should be replaced by a more nutritionally significant determination.