Cluster, Glass, and Crystal Formation in Protein Mixtures of Opposite Charge

Concentrated protein mixtures are ubiquitous in nature and widespread in many fields of technology. For example, living cells contain up to 300 mg ml^-1 of thousands of different proteins in their intracellular fluid. An interesting new development in the food sciences concerns “high protein foods”. These products contain large amounts of proteins and are thought to aid in the fight against obesitas and sarcopenia.
        While each organism or application may require a specific set of components and circumstances to function properly, perform optimally, or taste exquisitely, they certainly share one common requirement: stability. It is one of the biggest challenges in the field, as concentrated protein mixtures are prone to undergo many different types of phase transitions, such as crystallization, liquid-liquid phase separation, and complex coacervation.
        Our experiments on cluster, glass, and crystal formation in several concentrated binary protein mixtures reveal that instabilities can be greatly suppressed by careful tuning of the salt concentration, pH, and protein composition. These findings will contribute to a better understanding of complex biological and technological systems, such as dairy products and the intracellular fluid of living cells.