500 g tubers were taken randomly from each batch and chopped into small pieces. Inulin was extracted in hot distilled water accord-ing to Gao’s methods with minor modification (Gao, Peng, & Xu,2009). Firstly, the samples were boiled for 5 min to eliminate enzymes. Then they were stoved at 60◦C for 7 h and smashed witha grinder. The sample power was boiled in deionized water at 90◦Cfor 40 min twice and filtered. Ca(OH)2was added to the filtrate untilpH reached 11 to remove the protein, and H3PO4was added untilpH was 8 to remove the redundant Ca(OH)2. Then 30% H2O2(v/v3%) were used to bleach the solution. Finally, the inulin powder wascollected by precipitation with excess ethanol and freeze dried at−40◦C.