Chemical, Thermal and Physical Characterization of Inulin for its Technological Application Based on the Degree of Polymerization

Abstract

Abstract In this work was studied the effect of the degree of polymerization (DP) in two systems based on inulin. Understanding the relation between the chemical and physical properties, allows establishing the potential application for inulin according to its DP. Amorphous inulin powders were characterized by mass spectrometry to determine the DP. Inulin from chicory root and dahlia tubers showed a DP of 2–15 and 2–12, respectively. The systems were exposed to different water activities, finding sigmoidal curves type II. Thermal analysis showed two melting events, suggesting the presence of crystals differing in size. The glass transition temperature range widened and lowered in the high DP inulin. By X‐ray diffraction low DP inulin presented a moderate transition behavior while in high DP inulin was conducted abruptly. State diagrams for stability showed that high DP inulin must be stored at more rigorous conditions of temperature and humidity for avoiding unwanted crystallization effects. Practical Applications The results presented in this work are useful for: (i) relating the physical and thermal properties ( T m , T d and T g ) with the degree of polymerization of sugar‐rich systems such as inulin powders, (ii) set the optimal processing conditions in an industrial application such as spray drying process while avoiding product damage, and (iii) predicting the product stability based on the physical properties plotted in the form of a state diagram.