Towards animal-free dairy : investigating the impact of assembly conditions, composition adjustments, and casein modifications on casein micelles using reassembled sasein micelles

Using animal milk to produce dairy products has existed for a long time in human history. However, the modern dairy industry currently faces a new challenge related to sustainability. A possible novel approach to address this challenge is to produce milk proteins through precision fermentation. This process does not involve the use of animals and may improve the sustainability of dairy product production. One of the major challenges in using dairy proteins produced through precision fermentation to create dairy products is replicating the microstructure of milk, such as casein micelles, which play critical roles in the functionality of dairy products. For many dairy products, such as cheese and yogurt, the gelation of casein micelles is the first step in their production. Therefore, a critical step in producing animal-free dairy products is to assemble dairy proteins derived from precision fermentation into casein micelles. To build animal-free casein micelles with the desired properties and the flexibility to fine-tune them according to specific needs, a comprehensive understanding of casein micelles is essential. In this thesis, reassembled casein micelles (RCMs) are used as a tool to study casein micelles. The insights gained from this thesis were transferred to the development of animal-free dairy products. This thesis has four specific research objectives. The first is to understand the in vitro reassembly process of casein micelles. The second is to adjust the composition of reassembled casein micelles. The third is to examine the effects of casein molecule modifications on the behavior of RCMs. The fourth is to investigate the gel structures formed by casein micelles. This study found that, in order to obtain casein micelles suitable for producing animal-free dairy products using caseins from precision fermentation, both the casein micelle reassembly process and appropriate molecular modifications on caseins are essential.