Conventional and emerging pre-treatments for plant protein fermentation: prospects for next-generation plant-based...

The development of plant-based meat analogues (PBMAs) that accurately replicate meat texture and flavor remains limited by fundamental structural differences between plant and animal proteins. Most notably, the globular conformation of plant proteins contrasts with the fibrous anisotropy of animal muscle, thereby limiting viscoelasticity. Additional challenges include beany off-notes arising from lipid oxidation products such as hexanal and anti-nutritional factors (ANFs) that reduce bioavailability. Fermentation is a traditional technology increasingly explored as a strategy to address these limitations by modifying protein structure and functional properties, and by promoting the formation of savory volatile compounds. However, conventional processing and extraction of plant flours or meals to produce protein concentrates and isolates often induce protein aggregation, which restricts microbial access and limits proteolytic activity. This review critically appraises the potential of conventional and emerging pre-treatment technologies to modulate plant protein structure and improve fermentability and downstream quality attributes in PBMAs. It further proposes a structure-fermentation-function framework linking pre-treatment-induced structural alterations to microbial accessibility, proteolytic efficiency, and downstream techno-functional performance in plant-based meat analogues. Thermal pre-treatments offer industrial scalability but can cause excessive denaturation and loss of functionality. In contrast, emerging non-thermal approaches can enable matrix-dependent structural modification, with potential effects on enzyme accessibility and microbial interaction during fermentation. Studies on ultrasound (US), pulsed electric fields (PEF), and high-pressure processing (HPP) report changes in lipid oxidation, microbial performance, and proteolytic behavior through fermentation, although these effects remain substrate-, matrix-, and dose-dependent. Integrating optimized pre-treatments with controlled fermentation represents a promising route to modify the nutritional, functional, and sensory profile of PBMAs. Further research is needed to clarify the complex interactions between these complementary processes and evaluate downstream safety and regulatory considerations.