High-moisture extrusion of hempseed and oat press cakes for formation of soy-protein-containing fibrous meat analogs: Textural and physicochemical properties

Abstract

High-moisture extrusion (HME), a key technology for producing plant-based meat analogs with desirable fibrous structure, was applied in this study to develop formulations enriched with hempseed press cake (HPC), combined with soy protein isolate (SPI) and oat press cake (OPC) in ratios of 70:20:10 and 30:60:10 (HPC:SPI:OPC). These formulations were processed under different conditions of water content (50, 55, and 60 %) and long cooling die temperature (40, 60 and 80 °C) to investigate their effect on the textural and physicochemical properties of the extruded meat analogs. Partial least squares regression results revealed HPC and water content as the main drivers of textural and physicochemical properties. Low-HPC formulations yielded structurally resilient and fibrous textures, supported by texture profile analysis, standard and fluorescent imaging, and protein bond analyses. HPC enhanced the textural resemblance to cooked meat, reducing hardness, gumminess, and chewiness, while maintaining relatively high protein levels. Increasing water content softened the extrudates and decreased structural resilience, whereas long cooling die temperature had moderate influence, enhancing anisotropy and promoting protein bond formation at higher temperatures. Protein solubility assays indicated that hydrogen bonding was the dominant interaction stabilizing the fibrous structure, followed by disulfide bonding and hydrophobic interactions. Imaging analysis corroborated these findings, revealing more organized protein networks in low-HPC formulations. The incorporation of HPC improved nutritional value without compromising structural integrity. This study demonstrates the feasibility of using upcycled plant-based ingredients such as HPC and OPC in meat analogs. Through composition and process optimization, sustainable and nutritionally valuable products with meat-like texture can be achieved.