Structural deviations between native and precision fermentation-derived food proteins: Techno-functionality and structure formation strategies

Precision fermentation enables the production of animal-like proteins without the need for livestock. However, transforming these recombinant proteins into functional food ingredients remains challenging, as their molecular properties often differ from animal-derived counterparts. Furthermore, complete food products also require the integration of fat and carbohydrates. The review focusses on the structural differences commonly found in recombinant dairy, egg proteins and gelatin compared to their animal-derived counterparts and explores strategies to produce food analogues with these ingredients. Key differences include N-terminal extensions and differential posttranslational modifications such as glycosylation, which can significantly impact protein functionality. Proteolytic degradation in the recombinant host as well as the presence of non-target (protein) impurities can also alter the functionality. Food structuring using recombinant proteins can follow two main approaches. The bottom-up approach assembles individual proteins into aggregates with specific properties, such as casein micelles. This approach is strongly dependent on the molecular properties of the proteins, which can be modulated by structural deviations through the choice of the host and the genetic polymorph of the target protein. The alternative is a top-down approach, where specific process conditions are applied to a formulation that contains fat, proteins and carbohydrates in the required composition. This approach depends on macromolecular properties such as phase behavior and association of the ingredients and is therefore affected by the presence of non-protein components from the host. Based on the listed findings, future processes can be developed that take molecular and macromolecular properties of the recombinant protein ingredient into account.