Development and evaluation of extruded sorghum–soy chunks as a sustainable plant-based meat alternative

In response to the growing demand for sustainable plant-based protein alternatives, this study aimed to develop and optimize extruded sorghum–soy chunks as plant-based meat alternatives utilizing hot extrusion technology. The formulation comprised 20% sorghum flour and 80% defatted soybean flour. An analysis was conducted on the physical properties of sorghum grains and the chemical compositions of both sorghum and soy flour. Eight processing combinations (T1–T8) were established by varying the temperatures across three zones (65–140 °C), screw speeds (26 and 28 Hz), and feed moisture levels (28% and 30%). The extrudates were assessed for their physical, chemical, functional, porous structural, textural, and sensory characteristics to ascertain optimal processing conditions. Treatment T8, processed at 70 °C, 110 °C, and 140 °C in Zones 1, 2, and 3, respectively, with 30% feed moisture and a screw speed of 28 Hz, demonstrated the most favorable characteristics. T8 extrudates showed a bulk density of 1.48 ± 0.01 g/cm 3 and a tapped density of 1.55 ± 0.01 g/cm 3 . Protein content increased from 51.94 ± 0.02 to 56.47 ± 0.04 g/100 g (db), and fiber from 8.45 ± 0.04 to 13.54 ± 0.02 g/100 g (db). The expansion ratio was 8.10 ± 0.09%, with a water absorption index of 0.23 ± 0.05% and a water solubility index of 0.21 ± 0.02%. Textural attributes included hardness (69.97 ± 3.50 N), fracturability (28.45 ± 1.42 N), chewiness (11.75 ± 0.59 N), gumminess (17.80 ± 0.89 N), springiness (0.44 ± 0.02%), and cohesiveness (0.42 ± 0.02%). Based on functional, porous, and sensory evaluations, T8 was identified as the most acceptable formulation, possessing superior nutritional and structural characteristics suitable for plant-based meat alternatives.