Extrusion texturization of pea protein incorporating Sacha inchi (Plukenetia volubilis L.) press meal: Effects on structural, molecular interactions, and sensory properties of plant-based meat analogues

Sacha inchi ( Plukenetia volubilis L.) press cake (SP), a protein-rich byproduct of oil extraction, represents a promising ingredient for sustainable plant-based protein development. This study investigated the incorporation of steam-pretreated Sacha inchi press cake into pea protein isolate (PPI) for the production of textured vegetable protein (TVP) using single-screw extrusion. Steam pretreatment improved palatability by reducing tannin and saponin contents by 23.6% and 25.0%, respectively. The pretreated SP, referred to as Sacha inchi press cake meal (SPM), was blended with PPI at SPM:PPI (w/w) ratios ranging from 0 to100% to evaluate its effects on the structural, molecular, nutritional, and sensory properties of the resulting extrudates. Increasing SPM incorporation progressively disrupted the anisotropic fibrous network typical of well-structured TVP, producing a more porous and isotropic matrix, as observed by scanning electron microscopy. Fourier transform infrared spectroscopy indicated that residual polysaccharides and lipids in SPM interfered with intermolecular hydrogen bonding and β-sheet formation during extrusion, thereby limiting protein realignment at higher inclusion levels. At 10% SPM incorporation, the extrudate maintained a compact fibrillar structure with textural properties comparable to commercial TVP while providing high protein content (69.42%) and a favorable fatty acid profile dominated by oleic and linoleic acids. Application in Thai Pad Krapao demonstrated higher consumer acceptance than commercial TVP. These findings provide mechanistic insights into how lipid- and fiber-rich byproducts influence protein realignment during extrusion, offering a sustainable pathway for developing high-quality plant-based meat analogues.