Composition of bovine milk fat globules by confocal Raman microscopy

Confocal Raman microscopy was used to determine the chemical fingerprint of individual bovine milk fat globules of different sizes and from milk sourced from different breeds. No detectable level of triglycerides was found in the small milk fat globules of 1 μm diameter or less in size. These small fat globules also delivered information about the lipids of the milk fat globule membrane. In addition, the lipid composition varied according to the size of the globules with an increasing concentration of carotenoids and decreasing level of unsaturation with increasing diameter. The carotenoids content also varied according to the breed origin of the milk, with Jersey milk fat globules containing more carotenoids than the Friesian-Jersey milk fat globules. The results suggest that the milk fat globules have different properties according to their size.