Structural modifications and physical characteristics of high-moisture meat analogues using faba bean and Indigenous wild rice

Extrusion cooking is a thermo-mechanical process that transforms globular plant proteins into meat-like textures through complex structural modifications. While extensively studied for conventional proteins like soy, pea, and wheat gluten, these transformations remain unexplored for novel sources such as faba bean protein (FP). Furthermore, the incorporation of culturally significant ingredients like Indigenous wild rice (IWR) in high-moisture meat analogues (HMMAs) has not been investigated. This research aims to incorporate IWR into HMMA formulations and study the effects of extrusion temperatures (125, 135, and 145°C at the die) and feed moisture levels (50%, 54%, and 58%) on physical quality, protein-protein interactions, protein secondary structure and in vitro protein digestibility. IWR was successfully integrated into HMMAs at a 25% (w/w) concentration. Findings showed that extrusion temperature did not affect textural quality (cutting strength, hardness, and chewiness), whereas higher feed moisture reduced these properties. After extrusion, the in vitro protein digestibility improved slightly from 85% (raw FP) to 87% (HMMAs). Protein-protein interaction analysis indicated that the HMMA protein structure was stabilized by both covalent (disulfide bonds) and non-covalent interactions (hydrogen and hydrophobic bonds). An increased temperature enhanced hydrogen bonding, while higher moisture levels intensified disulfide bonds. This research provides fundamental insights into the structural changes occurring during HMMA formation, contributing to a deeper understanding of protein structure-function-digestion relationships. Moreover, it establishes IWR as a novel ingredient for producing HMMAs, promoting cultural inclusion in plant-based food systems. The next phase of this project aims to improve the flavor profile of HMMAs through innovative pre-treatments including fermentation and enzymatic hydrolysis.