Harnessing Rhizopus oligosporus mycelium as a sustainable protein source: Functional properties and optimization of a meat-analogue “chicken popcorn”

Mycoprotein represents a sustainable protein alternative, but its techno-functional properties relative to conventional sources remain underexplored. Soy and yeast proteins have been selected as representative plant- and microbial-based references commonly used in meat analogue development. Rhizopus oligosporus mycelium was explored as a novel fungal protein with potential as a sustainable, nutritionally balanced, and scalable ingredient for next-generation meat substitutes. Furthermore, a vacuum-fried “mycelium-based chicken popcorn” prototype was developed and optimized to resemble commercial meat analogue products. Soy protein (SP), yeast protein (YP), and R. oligosporus mycelial protein (RP) were characterized via amino acid profiling, SDS-PAGE, circular dichroism, fluorescence spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Functional properties including water-/oil-holding capacity, foaming, and sulfhydryl (–SH)/disulfide (S–S) contents were assessed. Response surface methodology (RSM) evaluated brine concentration, oil, and konjac glucomannan (KGM) with texture profile analysis (TPA). SP contained the highest hydrophilic amino acid proportion, contributing to superior water-holding capacity, while RP showed the highest oil-holding capacity. Heating treatment, increased –SH, and decreased S–S, indicating partial bond cleavage and exposure of buried thiols. RP exhibited the greatest thermal stability and the highest proportion of ordered secondary structures. RSM identified an optimal formulation (2.53 % brine, 5 % oil, 1 % KGM) producing mycelial-based chicken popcorn with hardness and chewiness comparable to a commercial plant (soybean)-based benchmark, differing only in springiness. These findings highlight the nutritional and structural advantages of R. oligosporus mycelium and its ability to generate meat-like textures, underscoring its potential as a scalable, sustainable protein source for alternative meat applications. • RP exhibited the highest oil-holding capacity, supporting its role in enhancing juiciness of meat analogues. • Thermal analyses revealed RP had the slowest thermal degradation and superior heat stability. • RP contained the highest proportion of β-sheets, suggesting potential to improve product hardness and chewiness. • RP-based mycelial “chicken popcorn” achieved commercial benchmark–like hardness and chewiness for meat analogues.