Fructan synthesizing and degrading activities in chicory roots (Cichorium intybus L) during field-growth, storage and forcing

An investigation of SST (E.C. 2.4.1.99) and FFT (E.C. 2.4.1.100) activities in chicory roots (Cichorium intybus L. var foliosum cv. Flash) showed that both enzymes also had a small but genuine beta-fructosidase activity The activity of fructan exohydrolase towards small and large fructans was comparable provided that they are present in the same molar concentration. During field growth the activity of SST decreased continuously to essentially disappear in October. FFT activities on the contrary remained high and even increased slightly Fructan exohydrolase activity was detected throughout field-growth bur in crude extracts a part of it is likely to be due to the beta-fructosidase activity of FFT. When this was taken into account the genuine fructan exohydrolase activity increased rapidly after mid-October. During cold storage a further rapid increase was detected. Forcing of the roots resulted in a considerable decrease of inulinase activity although large amounts of fructans are mobilized during that period.