Impact of extrusion processing on nutritional quality of chickpea-based snack products

Abstract:

The snack food industry faces a persistent challenge: how to produce crispy, shelf-stable products from pulse flours without destroying the very nutrients that make pulses attractive to health-conscious consumers. This research investigated the effects of extrusion barrel temperature (120°C, 140°C, and 160°C) and feed moisture content (14%, 18%, and 22%) on the nutritional quality, physical properties, and sensory acceptability of chickpea-based extruded snacks. Desi-type chickpea flour was processed in a co-rotating twin-screw extruder at a screw speed of 250 rpm. Total protein retention decreased from 94.2% at 120°C to 71.1% at 170°C, and available lysine declined even more sharply (89.7% to 58.4%). Expansion ratio peaked at 140°C and 18% moisture (3.24), coinciding with the highest sensory scores for crunchiness (7.9/9) and overall acceptability (7.8/9). In vitro protein digestibility improved from 71.3% in raw flour to 84.7% at 140°C, owing to the denaturation of trypsin inhibitors during extrusion. The results identify 140°C barrel temperature with 18% feed moisture as the optimal condition that balances nutrient retention, textural quality, and consumer acceptability for chickpea extrudates.