Microalgal Protein Isolate Cryostructurates: Understanding their role in Preserving the Biological Activity of Lacticaseibacillus rhamnosus GG under Processing, Storage, and Gastrointestinal Transit Associated Cell Stressors

Probiotics are “good bacteria” that can support digestion, immunity, and even other parts of the body such as the brain and skin. However, they are very sensitive. During production, storage, and digestion, many cells can be damaged before they reach the intestine, which reduces their health benefits. This PhD research studied how natural proteins from microalgae, such as spirulina and chlorella, can help protect probiotics in food supplements. Compared with commonly used dairy and pea proteins, microalgal proteins showed strong protective effects during drying, long-term storage, and digestion. Their effectiveness is linked to how they bind water and how they behave under acidic stomach conditions. The research also explored structured systems combining microalgal proteins with alginate, a natural ingredient from seaweed, to further improve stability and support gradual release in the gut. Overall, this work contributes to the development of more reliable, dairy-free, and environmentally friendly probiotic products.