SOURCES OF ERROR IN DIETARY FIBER ANALYSIS

The following error sources in the present dietary fibre (DF) analytic al methods were investigated: (1) the omission of the protease treatme nt of samples may modify the results by increasing the Klason lignin f raction and altering the content and/or distribution of polysaccharide s; (2) some soluble dietary fibre (SDF) constituents can be retained i n the insoluble dietary fibre (IDF) matrix affecting the insoluble and soluble fraction distribution; (3) protein, ash and blank corrections in gravimetric analysis involve a lack of precision, over- or under-v aluing the actual DF contents; (4) the Klason lignin fractions obtaine d by acid hydrolysis of DF residues are made up of different component s and artifacts besides lignin. These studies included both new observ ations and additional quantitative evidence on error sources previousl y mentioned in the literature. In some cases the published methods wer e modified to emphasize the methodological errors.