Abstract: The HPLC was run on an Ultrahydrogel 250 column (7.8×300 mm) with refractive index (RI) detector for determinations of content and average molecular weight of polydextrose in some samples. Distilled water was used as the mobile phase at a flow rate of 0.5 ml/min. The correlation equation was established between molecular weight and retention time and applied to estimate the molecular weight of polydextrose samples. The calibration curve was linear over the polydextrose concentration range of 0.199～3.98 mg/ml, with a correlation coefficient of r=0.9998. The polydextrose mass recovery ranged from 103% to 110% with a RSD of 1.91%. The method is found to be simple, reproducible and reliable, and thus ideally suitable for the analysis of polydextrose in food product.

Key words: HPLC, soluble dietary fiber, polydextrose