This method determines total dietary fiber in foods and food ingredients, as defined by the Codex Alimentarius Commission. The method quantitates high molecular weight dietary fiber (HMWDF), including resistant starch (RS), and low molecular weight soluble dietary fiber (LMWSDF), including nondigestible oligosaccharides. In this method, enzymatic digestion at 37°C is used to simulate human intestinal digestion, followed by gravimetric isolation to quantitate HMWDF and high-performance liquid chromatography (HPLC) to quantitate LMWSDF. The method measures the complete range of dietary fiber components from RS
(by utilizing the digestion conditions of Method 32-41.01) to digestion-resistant oligosaccharides (by incorporating the deionization and HPLC procedures of Method 32-40.01) (Fig 1).