A rapid determination of the total sugar content and the average inulin chain length in roots of chicory (Cichorium intybus L)

A method is proposed to the chicory breeder for the fast screening of total sugar content and average inulin chain length of lots of chicory roots. The determination of the refractive index of the chicory root juice by refractometer is the first step. This rapid analysis gives a good estimation of the total sugar content (r=0·85; RSD=3·8%). In the next step extracts of chicory roots with a high total sugar content are hydrolysed and analysed by chromatography. The calculated fructose/glucose ratio predicts the average inulin chain length well (r=0·91; RSD=5·3%). The molecular weight distribution of the inulin was analysed by anion exchange HPLC with pulsed amperometric detection.