Influence of variety, date of harvest and storage time on factors connected with the crystallisation on canned scorzonera (Scorzonera hispanica)

In the period 1983-1986, research was carried out into the inulin content of scorzonera during ripening and storage. Since the inulin content is determining for the occurrence of crystallisation with canned scorzonera, the effects of the varieties, the time of harvest and storage of the scorzonera were investigated. The changing of the inulin content on the conversion into reducing sugars was checked; the effect of the dry matter and nitrate content were also defined. The aim was to define whether the determination of the inulin content was a useful parameter for the ripening of the scorzonera. On the whole, the different varieties showed remarkable differences where fructosanes + inulin, as well as pure inulin, were concerned. A significant decrease of the inulin content was obtained from the middle of November, by so far that it was below the limit above which crystallisation takes place. A two-month storage period of scorzonera harvested in early October also led to a very low inulin content, so that no problems could occur while canning. Storage conditions of the scorzonera seemed of importance too. The nitrate content of the different scorzonera varieties was low, although some variations were noted. The crops harvested in early December showed considerably lower contents when compared to those harvested in early October or mid-November. The inulin content as well as the content of reducing sugars are a useful parameter to determine the maturity of the scorzonera.