Investigation of process and product parameters on physical attributes, resistant starch, and in vitro starch digestibility of modified rice flour‐based extruded snacks

Abstract

Modified rice flour (MRF) with higher resistant starch content was explored to produce resistant starch, enriched extruded snacks. Effects of feed moisture (10%–35%), temperature (130–180°C), and screw speed (150–200 rpm) on specific mechanical energy input (SME), expansion ratio (ER), breaking strength (BS), L*, a*, and b* values, resistant starch (RS), predicted glycemic index (pGI), glycemic load (GL), and sensory evaluation of extrudates were investigated. Moreover, independent variables influenced both machine and product responses significantly (p < .05). Design expert predicted feed moisture of 26.90%, temperature of 130°C, and screw speed of 193 rpm as desirable conditions for the development of MRF extrudates. pGI decreased from 75.83 in control to 68.41 in the developed MRF extrudates. Novelty statement Resistant starch content increased from 4.12% in native rice flour (NRF) extrudates to 7.16% in MRF extrudates. Predicted glycemic response decreased from 75.83 in NRF extrudates to 68.41 in MRF extrudates. Moisture content of 26.90%, screw speed of 193 rpm, and temperature of 130°C were predicted as optimum extrusion cooking conditions. Using pregelatinized rice flour in the preparation of extrudates proved to be a novel way to decrease the glycemic index and glycemic load of rice-based snacks.