Effect of Xanthan Gum Synergistic Dry Heat Treatment on the Structural and Physicochemical Properties of Chinese Wild Rice Starch

In order to investigate the effects of xanthan gum synergistic dry heat treatment (DHT) on the granule morphology, particle size distribution and size, short-range ordered structure, crystal structure, solubility and swelling degree, pasting properties, thermal properties and gel texture of Chinese wild rice starch (CS), this study used different concentrations of xanthan gum (0%, 0.1%, 0.3%, 0.5% and 0.7%) to compound wild rice starch and perform dry heat treatment at 130 ℃ for 2 h. The results showed that xanthan gum synergises with dry heat treatment promoted the aggregation of natural wild rice starch granules. The average particle size of CS-DHT-0.7XG increased significantly from 1.78 µm to 3.21 µm (P<0.05). Compared with CS-DHT, the short-range order, degree of double helix, and relative crystallinity of Chinese wild rice processed with xanthan gum synergistic dry heat treatment all increased with increasing xanthan gum concentration in the system, whereas the solubility and swelling power were limited. The results of the pasting properties revealed that the peak viscosity of CS-DHT reached the maximum value (5589.33 mPa.s) and the pasting temperature reached a minimum value (73.67 ℃), whereas the CS processed with a high concentration of xanthan gum (0.7%) synergistic dry heat treatment reached the maximum value of setback (3323.67 mPa.s). In addition, xanthan gum synergised with dry heat treatment increased the enthalpy value of CS and the hardness of the gel, and reduced the gumminess of the gel. The results of this study can provide new insight into the modification of CS.