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

Abstract

The degree of polymerization (DP) of inulin is the number of monomer units in inulin polymer strand. DP inulin can be determined simply using spectrophotometer. This study aims to determine DP inulin from fresh dahlia tubers and dahlia tubers that are 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 in 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-Sulfate method, the absorbance was measured at λmax 350 nm. Inulin from fresh dahlia tubers had average DP higher than inulin from dahlia tuber that stored for fifteen days. Inulin that found in this research belongs to the fructooligosaccharide (FOS) group.