Abstract
The demand for sustainable, plant-based protein alternatives has driven significant interest in pulse protein texturization via high-moisture extrusion processing. This study investigated the continuous twin-screw extrusion texturization of binary protein blends consisting of pea protein isolate (PPI) and faba bean protein concentrate (FPC) at a 60:40 dry mass ratio. The influence of barrel temperature profile (120, 140, and 160 °C) and feed moisture content (55, 60, and 65% w/w) on specific mechanical energy (SME), fibrous anisotropy index, water-binding capacity (WBC), and microstructural arrangement was systematically evaluated. Results demonstrated that increasing the barrel temperature up to 140 °C promoted optimal protein unfolding and macromolecular alignment, enhancing the fibrous anisotropy index from 1.21 to 1.88. However, an excessive temperature of 160 °C induced thermal degradation and weakened the anisotropic structure. Higher feed moisture contents (65%) diluted the melt viscosity and reduced SME input, leading to lower mechanical anisotropy but significantly increasing the WBC (up to 3.42 g H2O/g dry extrudate) through the creation of expanded capillary hydration networks. Microstructural analysis via scanning electron microscopy confirmed the formation of continuous, parallel fiber bundles at 140 °C and 60% moisture. These findings establish that optimizing thermal and hydration parameters enables the tailored texturization of pulse protein blends for realistic meat substitute applications.
