Abstract
Comparing the food composition of dahlia tubers with those of inulin-rich foods such as Jerusalem artichoke, chicory and edible burdock, we found that dahlia tubers were a good source of inulin, a soluble dietary fiber. We investigated the feasibility of using dahlia tubers which have been discarded because they lack buds as a food source for inulin. Dahlia inulin was extracted and purified as follows : after draining the first hot-water extracts from sliced tubers, the tubers were ground by electric mixer, boiled, and subjected to filtration. The filtrate was decolorized and deodorized using activated charcoal and then concentrated by boiling. Inulin was precipitated by addition of 4 volumes of ethanol and subsequently refined using 80% ethanol for food use. The average purities of inulin before and after refining were 83.2% (n=16) and 97.9% (n=8). We confirmed the absence of atropine in hot-water extracts of dahlia tubers using Dragendorff reagent and HPLC methods. Based on data obtained from addition and recovery of atropine to purified inulin, we concluded that dahlia tubers and the purified inulin obtained in this experiment were free from atropine.
