Effects of Different Extraction Methods on the Gelatinization and Retrogradation Properties of Highland Barley Starch.

The purpose of this study was to compare the gelatinization and retrogradation properties of highland barley starch (HBS) using different extraction methods. We obtained HBS by three methods, including alkali extraction (A-HBS), ultrasound extraction (U-HBS) and enzyme extraction (E-HBS). An investigation was carried out using a rapid viscosity analyzer (RVA), texture profile analysis (TPA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectrometry (FTIR). It is shown that the different extraction methods did not change the crystalline type of HBS. E-HBS had the lowest damaged starch content and highest relative crystallinity value ( p < 0.05). Meanwhile, A-HBS had the highest peak viscosity, indicating the best water absorption ( p < 0.05). Moreover, E-HBS had not only higher G' and G″ values, but also the highest gel hardness value, reflecting its strong gel structure ( p < 0.05). These results confirmed that E-HBS provided better pasting stability and rheological properties, while U-HBS provides benefits of reducing starch retrogradation.