The Size Distribution of Casein Micelles in Camel Milk

The size distribution of casein micelles in camel milk has been determined by electron microscopy. Individual and pooled samples were cryo-fixed by rapid freezing and freeze-fractured. Electron micrographs of the freeze-fracture replica revealed a relatively broad size distribution, with an average micelle diameter around 280 nm in the volume distribution curve. The distribution was significantly broader than that of the particles of cow's or human milk and showed a greater number of large particles. The submicelles were also somewhat larger than those observed in cow's and human milk (approx. 15, 10 and 7 nm, respectively). The average values for the gross composition of camel milk were similar to those of cow's milk. Partition of mineral salts between the serum and micellar phase of camel milk was studied by means of ultrafiltration. The proportion of soluble forms of the minerals expressed as percentage of their total concentrations were 33% for calcium, 69% for magnesium, 52% for phosphorus and 60% for citrate. Initial paper received February 22, 1989 Manuscript received June 22, 1989 Direct inquiries to Z. Farah Telephone number: 41-1-256 5378