Fabrication of mycelium-gellan gum hybrids as next generation alternative protein foods produced by fermentation

Abstract

The growing demand for a more sustainable and nutritious food supply has increased interest in replacing animal-derived foods with those from alternative sources, such as fermentation processes. However, creating foods entirely from ingredients generated using a single fermentation process is often challenging. Consequently, there is interest in combining different sources of fermentation-derived ingredients to create foods with improved physicochemical, sensory, and nutritional properties. In this study, we examined the potential of combining two functional ingredients obtained using microbial fermentation. Mycoprotein (MCP) is a protein-rich material derived from mycelium fermentation that can form fibrous meat-like structures and has good nutritional properties, but it has poor gelling properties, which limits its ability to create meat substitutes and analogs. High acyl gellan gum (HA-GG) is a polysaccharide derived from bacterial fermentation that has excellent gelling properties. We therefore combined MCP and HA-GG to create hybrid hydrogels suitable for formulating meat substitutes and analogs. Differential scanning calorimetry, dynamic shear rheology, texture profile analysis, and scanning electron microscopy were used to assess the thermal, rheological, textural, and structural properties of MCP + HA-GG hydrogels with different compositions. The pure MCP (10 w/w%) samples did not exhibit any strong thermal transitions when heated or cooled from 10 to 90 °C. In contrast, pure HA-GG (2 w/w%) melted when heated above 85 °C and gelled when cooled below 80 °C. The MCP + HA-GG hybrids maintained a high shear modulus during both heating and cooling, which may be useful for food applications. The hybrids had an appreciably higher gel strength (Young's modulus, hardness, and shear modulus) than the individual MCP or HA-GG samples, which was attributed to a synergistic interaction between these two components. The gel strength, breaking stress, and breaking strain increased with increasing gellan gum concentration (0.5 to 2.0 w/w%), which meant that the mechanical properties of the hybrid materials could be tailored for specific applications. This study highlights the complex interactions among ingredients from alternative sources and their significant impact on the properties of food matrices. This information may be useful for formulating meat substitutes and analogs with enhanced physicochemical and functional properties.

Keywords: Dietary fiber; Gellan gum; Mycelium; Plant-based foods; Soft matter physics.