EVALUATION OF DIETARY FIBER IN POTATO CRISPS - INFLUENCE OF THE ANALYTICAL METHOD USED

Dietary fiber in ready salted potato crisps was determined by two meth ods, i.e., the official AOAC method, and the modified method of Englys t, recommended in the U.K. The ultimate aim was to compare the results and to evaluate the advantages and limitations of each method for the analysis of this food in order to obtain a figure to be included on t he package. The AOAC method is an enzymatic-gravimetric procedure to d etermine the total dietary fiber (TDF). The Englyst method consists of an enzymatic-chemical extraction and fractionation of the nonstarch p olysaccharides (NSP) and their subsequent determination as neutral sug ars by GLC. We modified the original chromatographic method. The AOAC method gave a value of 5.39 g/100g (dry matter) for TDF, and the Engly st method a value of 1.70 g/100g (dry matter) for NSP. It is assumed t hat the gravimetric method gives a higher fiber value than the Englyst method due to a contribution from retrograded starch. For this partic ular food, the AOAC method is faster and much easier to carry out and does not overestimate dietary fiber, if the resistant starch is regard ed as part of it.