A comparative study of high-performance liquid chromatography and colorimetric method for inulin determination

Inulin and oligofructose exhibit valuable nutritional and functional attributes, and so the utilization of inulin and its derivatives in the food industry has been continuously increasing. Compared with high-performance liquid chromatography (HPLC) which presents improved sensitivity and precision, colorimetric method is more widely used and accepted due to the advantages of its simplicity and economy. In order to determine inulin for the purpose of labeling, we develop an easy and effective HPLC method after extraction of inulin. HPLC conditions include a Shim-pack SCR 101C column (Shimadzu), deionized water at 80 A degrees C as the mobile phase, and a refractive index detector (RID). Moreover, we compared the HPLC method and colorimetric method on tested foods including claimed commercial inulin products such as inulin, inulin oligomers, and commercial food products. The obtained results demonstrated that the HPLC method could avoid the overestimation and inaccuracy caused by colorimetric method in the case where the samples contain glucan or sucrose, and be regarded as an approach which is easier, faster, and more accurate than colorimetric method for the routine quantification of inulin and inulin oligomers in commercial products.