Effect of heat moisture treatment on physicochemical and morphological properties of wheat starch and xylitol mixture.

The effect of heat moisture treatment (HMT, 100°C, 10h) on the physicochemical and morphological properties of wheat starch and xylitol mixture (SX) were studied by using Rapid Visco-Analyser (RVA), differential scanning calorimetry (DSC), scanning electron microscope (SEM) and X-ray diffraction pattern (X-ray). The research found that the peak viscosity (PV), trough viscosity (TV), final viscosity (FV) and breakdown (BD) of SX decreased markedly after HMT, whereas pasting temperature increased. Compared with SX, To, Tp and Tc of SX treated with HMT (H-SX) increased and ΔH decreased. The results of SEM showed that numerous xylitol granules appeared on the surface of starch granule in SX, and a layer of similar membrane adhered on the surface of starch granules in H-SX. After gelatinization and freeze-dried, the gel network structure of H-SX was tighter than that of SX. The amorphous region of H-SX was higher than that of SX.