Goat milk caseins: compositional variation, heat-induced changes, and coagulation properties

Casein micelles are key structural elements of many dairy products. As goat milk and its products exhibit different properties than cow milk, investigating goat casein micelles is relevant for improving our understanding of goat milk and products thereof. The thesis starts with an introduction of caseins and casein micelles, distinguishing between general structural and functional aspects of caseins, and highlighting goat casein specific aspects. Chapter two and three of this thesis focus on compositional variation among goat casein micelles. The compositional variation of goat casein with regard to casein composition, casein micelle size, protein content, and salt composition was studied using individual goat milk samples. Additionally, the genetic goat casein variants were identified using LC-MS. Furthermore, their effects on casein composition, casein micelle size, and protein content were analyzed. The chapter four and five focus on functional aspects of goat milk caseins. The acid and rennet gelation properties, as well as casein micelle properties of cow and goat milk and how these change upon heat treatment were investigated. Cow and goat milk caseins/ milk gels were compared using a variety of different techniques, including SDS-PAGE, rheology, neutron scattering, and spin-echo neutron scattering. Finally, the results are discussed with some additional results in the final chapter, to highlight differences between cow and goat caseins. Additionally, suggestions for future research on goat casein composition and casein functionality are discussed.