Pasting and Rheological Properties of Non-Crystalline Granular Starch

The pasting and rheological properties of non-crystalline granular starch (NCGS) are investigated and compared with those of partially or totally gelatinized starch. At low (65 and 70 degrees C) temperatures, non-gelatinized or only slightly gelatinized starch granules with a low viscosity and high flowability are dominant in the system. At intermediate treatment temperature (75 degrees C), the level of starch swelling and amylose leaching can be controlled to produce NCGS and its pasting and rheological properties fall somewhere between that of the partially and completely gelatinized starch. At high treatment temperatures (80 degrees C or higher), the starch granules completely collapse and amylose leaches out, leading to the formation of 3D network structures with amylopectin as the disperse phase and amylose as the continuous phase, accounting for the greater hysteresis, higher upper limits of LVR, and lower maximum compliance values. The distribution pattern of amylose and amylopectin is further emphasized to explain the unique pasting and rheological characteristics of NCGS. These findings suggest that starch-based foods with a wide range of rheological properties can be formed from the same starting material by strictly controlling the thermal processing conditions.