Investigating different gel structures formed by bovine casein micelles, goat casein micelles, and reassembled casein micelles.

This proposal describes a new approach to making animal-free dairy products by producing casein from microorganisms and then assembling them into casein micelles. The gelation of casein micelles is an essential step towards dairy products such as yoghurt and cheese. To investigate the possibility of making dairy products with this approach, we would like to compare the gel structure formed by native casein micelles (extracted from milk) with reassembled casein micelles (made with lab-purified caseins). Small-angle X-ray and neutron scattering have been shown to be a suitable method to describe the internal structure of casein micelles. However, after acidification or renneting, casein micelles tend to aggregate, and the aggregated structures are too big for small-angle scattering. Spin-echo small-angle neutron scattering (SESANS) has been shown to be a powerful tool for investigating milk gels (Tromp & Bouwman, 2007). Therefore, we would like to apply SESANS measurement on native casein micelles (NCMs) and reassembled casein micelles (RCMs) gels to investigate their gel structures. We will prepare 5 types of micelles including NCMs from bovine and goat milk, RCMs made with bovine and goat casein composition and RCMs with increased beta-casein content. We will also apply a heat treatment on those micelles. With this experiment, we expect to gain important knowledge on how casein micelles source, casein composition and heat treatment affect the gel structure formation.