Evaluation of size distribution of fat globules and fat and protein content in Estonian Goat milk
Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, EE51014 Tartu, Estonia, *Correspondence: vilma.tatar@emu.ee
Abstract:
The objectives of this study were to investigate size distribution of fat globules, fat and protein content in Estonian goat milk. The bulk milk samples were collected from three different crossbreed goat herds. These herds consist of 30% of the Saanen breed and 70% did not belong to any certain breed. Lactation of goats was scattered over the year. Goat milk samples were examined weekly during a 10 month period. Fat and protein content in goat milk ranged from 3.09% to 5.04% and from 2.74% to 3.96% respectively. Fat content in cow milk ranged from 3.77% to 4.75% and protein content ranged from 3.14% to 3.75%. The average fat content in goat milk (3.88%) was less than the mean fat content in cow milk (4.0%). The average protein content in goat milk (3.41%) was higher than the mean protein content in cow milk (3.38%). Depending on the season, fat and protein content in goat milk varied by as much as 0.38% and 0.28% accordingly. The diameter of milk fat globules (MFG) was estimated using microscope Nikon SMZ 1000, equipped with the digital camera Nikon DS-U2/L2 USB and the software NIS-Elements D3.1. The average diameter of fat globules was 2.22 μm, ranging from 0.34 to 6.99 μm. The average size distribution of MFG had unimodal and slightly right skewed shape: 5.7% of globules were in range 0.5–1.0 μm, 15.9% in range 1.0–1.5 μm, 22.1% in range 1.5–2.0 μm, 21.0% in range 2.0–2.5, 16.1% in range 2.5–3.0 μm, 10.0% in range 3.0–3.5 μm, 4.3% in range 3.5–4.0 μm, 0.9% in range 4.5–5.0 μm.
Key words:
fat, fat globules size distribution., goat milk, protein