Functional fungal extracts from the Quorn fermentation co-product as novel partial egg white replacers

The production of mycoprotein biomass by Marlow Foods for use in their meat alternative brand Quorn is a potential source of sustainable alternatives to functional ingredients of animal origin for the food industry. The conversion of this viscoelastic biomass into the Quorn meat-like texture relies on functional synergy with egg white (EW), effectively forming a fibre gel composite. In a previous study we reported that an extract (retentate 100 or R100) obtained from the Quorn fermentation co-product (centrate) via ultrafiltration displayed good foaming, emulsifying and rheological properties. This current study investigated if a possible similar synergy between EW and R100 could be exploited to partially replace EW as foaming and/or gelling ingredient. The large hyphal structures characteristic of R100 solutions were observed in EW-R100 mixtures, while EW-R100 gels showed dense networks of entangled hyphal aggregates and filaments. R100 foams prepared by frothing proved less stable than EW ones, however a 75/25 w/w EW-R100 mixture displayed a similar foam stability to EW. Simlarly R100 hydrogels proved less viscoelastic than EW ones, however the viscoelasticity of gels prepared with 50/50 w/w and 75/25 w/w EW-R100 proved similar to those of EW gels while 75/25 w/w EW-R100 gels displayed similar hardness to EW ones. Both results highlighted a functional synergy between the R100 material and EW proteins. In parallel tensiometry measurements highlighted the presence of surface-active material in EW-R100 mixtures contributing to their high foaming properties. These results highlighted the potential of functional extracts from the Quorn fermentation process for partial EW replacement as foaming and gelling agent, and the complex nature of the functional profile of EW-R100 mixtures, with contributions reported for both hyphal structures and surface-active material.