New Fructan Series

Fructans of chicory comprise of linear molecules containing only (3 2,1 linked fructose, terminal glucose and terminal fructose (7) as in Helianthus tuberosus (74,112). Chromatographic profile of fructans using highperformance anion exchange chromatography (HPAE) combined with pulsed amperomatric detection (PAD) showed the presence of a second fructan series in stored roots of Cichorium intybus (113). Although the inulin series was dominant, the second fructan series was clearly present. This new series of fructans are present only in trace amounts in tubers of Helianthus tuberosus. The new fructans have a minimum of two terminal fructose moieties and no terminal or internal glucose as indicated by methylation analysis and identification of hydrolyzed products. These fructans appear as a homologous series up to at least DP 18. The nomenclature of Lewis (114) suggests that the new fructan series is inulo-n-ose. Therefore, these oligosaccharides could be named as inulobiose, inulotriose etc.

The amount of inulo-n-ose in chicory roots was rather high after just 3 weeks of cold storage. It was suggested that the amount of new fructan series in chicory depends on the physiological state-specifically whether inulin synthesis or mobilization is occurring. If pure inulin is required roots should be harvested at the time of active fructan synthesis (113).

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