Simple Determination of Inulin Polymerization Degree Average from Dahlia Tuber Using Spectrophotometer

Degree of polymerization (DP) of inulin is the number of monomer units in inulin polymer strand. DP of
inulin can be determined simply using spectrophotometer. This study aims to determine DP of inulin
from fresh dahlia tubers and dahlia tubers that stored for fifteen days. Inulin extraction from dahlia tuber
was based on the solubility of inulin in hot water and precipitation in ethanol by adding ethanol to final
concentration of 80% solution. Reducing sugars of inulin was determined using the DNS method. The
absorbances were measured using spectrophotometer at maximum wavelength of 490 nm. Total sugar
of inulin was determined using Phenol-sulphate method, the absorbance was measured at λmax 350
nm. Inulin from fresh dahlia tubers had higher DP than inulin from dahlia tuber that stored for fifteen
days. Inulin that found in this research belongs to the fructooligosaccharide (FOS) group.