Physicochemical characteristics of high pressure gelatinized mung bean starch during recrystallization

Abstract

The changes in physicochemical and structural properties of Ultra high pressure (UHP) gelatinized mung bean starch were investigated during 0 to 196h retrogradation process by using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). XRD analysis showed that the UHP-gelatinizated granules regenerated its original C-type crystallinity structures after retrogradation. The swelling power and solubility of native starch were increased with the increase in the assay temperatures from 50 to 90°C, while the changing trend of the retrogradated granules was more gradual over entire assay temperatures. In addition, retrogradated granules showed a progressive decrease in the light transmittance and an increase in the amount of resistant starch as the ageing time increased from 0 to 192h. DSC analysis suggested a slight increase in the transition temperatures (To, Tp and Tc) and the retrogradation enthalpy as the storage time increased. In contrast no endothermic transition peak could be observed using DSC after storage of heat-gelatinized mung bean starch gel.

Keywords: Crystallization; Pasting; Recrystallization; Retrogradation; Swelling.