Linking variation in the casein fraction and salt composition to casein micelle size in milk of Dutch dairy goats

The casein composition, salt composition, and micelle size varies substantially between milk samples of individual animals. In goats, the links between those casein characteristics are unknown and could provide useful insights into goat casein micelle structure. In this study, the casein and salt composition of 42 individual Dutch goats from 17 farms was studied and linked to casein micelle size. Micelle size, the proportions of individual caseins, and protein content were associated with one another. Milk with smaller casein micelles was higher in protein content, salt content, and proportion of alpha s1-CN, but lower in alpha s2-CN and (3-CN. The higher salt content in milk with small casein micelles was mainly attributed to a higher protein content, but changes in casein composition might additionally contribute to differences in mineralization. The nonsedimentable casein content in goat milk correlated with nonsedimentable fractions of (3-CN and kappa-CN and was independent of micelle size. Between large and small casein micelles, goat casein micelles than bovine micelles, indicating differences in internal milk was similar to casein mineralization in bovine milk, indicating that mineralization of casein micelles follows derstand how composition and micelle structure in goat milk are related to each other, which may be useful to in the future.