Milk from French-Alpine goats and Holstein cows was
obtained from a bulk tank immediately prior to analyses.
Fat globule size was determined by laser particle size
analysis. Individual globules of fat in goat milk ranged
from 0.73 to 8.58µm in diameter. The average diameter
of particles based on volume to surface area ratio (dvs)
was 2.76µm and was less than the mean (dvs) of 3.51
µm for bovine milk, in which fat globules ranged from
0.92 to 15.75µm in diameter. The specific surface area
of particles in caprine milk was 21,778 cm
2
/ml, whereas
the specific surface area of particles in bovine milk was
17,117 cm
2
/ml. Ninety percent of the total particles found
in goat milk were less than 5.21µm in diameter, whereas
90% of the total particles in bovine milk were less than
6.42µm based on the volume frequency distribution.
Dissociation of casein micelles by urea in goat whole and
skim milk caused larger dvs values due to the effect of
fat particles and reduced the specific surface area in both
milks because the total number of detectable particles
in both whole and skim milk was reduced.
(Key words:fat globule, size, particle, goat milk)
Abbreviation key: dvs=volume/surface average diameter,RI=refractive index (indexes),SSA=specific surface area.