Comparative Study on Effects of Xanthan Gum at Different Concentrations on the Functional, Thermal, and Digestibility Characteristics of Corn and Sorghum Starch Extrudates

The present study assesses the concentration dependent effect of xanthan gum, that is, 0%, 0.5%, 1%, and 2% (w/w), at 50% feed moisture, on the in vitro digestibility of corn and sorghum starch extrudates. Sorghum starch, being extracted from an underutilized and drought-resistant crop, provides a promising alternative to corn starch in the future. X-ray and Fourier transform infrared (FTIR) results show that xanthan gum at 1% has optimum synergistic interaction with corn and sorghum extrudates. The percent crystallinity, FTIR ratio (1047 cm(-1)/1022 cm(-1)) and melting enthalpy are minimum at 1% for both corn (ECX1) and sorghum (ESX1) extrudates along with maximum resistant starch (RS) fraction. The highest RS (70.51%) with the least predicted glycemic index (61.16) is observed for ESX1. Xanthan gum incorporation increases the peak viscosity and decreases the hardness of extrudates. The corn and sorghum extrudates prepared in the present study can be used for the development of low-calorie products due to the increase in RS content.