Physic-chemical Characteristics, Triglycerides and Fatty Acids Composition of Shami Goat Milk Fat

Afaf Masmas
General Commission for Scientific Agricultural Research-
Center, Food Technology Division
Faculty of Agriculture, Damascus University,
2009

Abstract

The study was conducted on (58) Shami goat milk samples taken periodically during milking period in 2008 (from January to September) and at (8-4) samples per month. Shami goats milk fat  was obtained from (40) sample separation of milk cream by automated Ecremeuse then converted by the mixer to cream and butter and then turned to margarine by dissolved in the water bath and separation the plasma from fat on the purification of  fat through anhydrous sodium sulfate.
Samples of milk and colostrum were chemically and physically tested to determine the chemical composition (total solids, non-fat solids, fat, protein, lactose and ash), and physical-chemical characteristics (pH, relative density, the pH). Then they were compared with cow’s milk, where the results showed a high percentage of fat, protein and ash content and therefore a high percentage of the total solids in goat milk compared with cow’s milk, while the proportion of lactose in goat milk is lower than in cow’s milk. The acidity, relative density and pH of Shami goats milk were similar to those in cow’s milk. Changes in both chemical composition and properties physicist – chemical for milk during lactation were also studied, showing an increase in total solids, fat, protein and lactose in the first month from the stage of lactation and then declined slightly in the third month and to increase again until the end of the stage of lactation. Percent ash was low in the first month and then rose in the other months from the stage of lactation. High acidity of Shami goats milk and intensity in the early stage of lactation was also found.
The results of  physic-chemical tests for Shami goats milk fat (pH, saponification number, the number of  iodate, the relative density, refractive index, the degree of fusion), showed that the fat of goat milk has the lowest values for the iodized number and higher values of saponification number, while it  has the lowest refractive compared with the cow’s milk fat. The pH values are similar in both types.
No significant change in the physic-chemical properties goat milk fat during lactation.
We separated and identified the composition of  the triglycerides of Shami goat milk fat during lactation by using the device (HPLC) and compared with cow’s milk fat. The results showed that the fat of goat’s milk contains a high proportion of  triglycerides (C26-C36) (24.15% compared to21%), and it has also a high proportion of the triglycerides (C38-C44) (49. 58% versus 36%). On the contrary, the ratio of  triglycerides (C46-C54) were lower in goat milk fat compared with cow’s milk fat (26.20% vs. 43%).
The results showed  that it did not significantly affected by lactation stage in the installation of triglycerides.
Also, the composition of  fatty acids of Shami goats milk fat has been isolated and identified during lactation using (GC), so the results confirmed that the goat milk fat contains a higher proportion of the following fatty acids: Cabreuec, Cabrelic, Cubric, Luric, and medium and short-chain saturated fatty acids compared with cow’s milk.
It also contains a higher proportion of fatty acid linoleic, while
containing less than Butric  acid in the cow’s milk fat, the results showed that there are no significant changes in fatty acids of goat milk fat during lactation.