Department of Food Technology, General Commission for Scientific Agricultural Research (GCSAR)
Faculty of Agriculture, Damascus University
The aims of this study was to identify the chemical composition of Shami goat milk, by studying (81) sample of Shami goat milk, taken periodically in karahta center for breeding Shami goat for the entire herd during the milking season in 2015 (from Janury to September) on a rate of 3 samples per month and 3 replications for each sample. The samples of the milk were conducted for chemical and physical tests (total solids, Un fat solids, fat, protein, lactose, ash), and physicist- chemical characteristics (pH, relative density, the p H), and compared with cow’s milk, 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, The proportion of lactose in goat milk was lower than in cow’s milk, but the acidity and the relative density and the p H of Shami goats milk were similar to those in cow’s milk. The changes in chemical composition and properties physicist – chemical for milk during lactation were turned out to increase the ratio of total solids, fat, protein and lactose in the first month of lactation and then declined slightly in the third month until the end of the lactation stage, The proportion of ash was low in the first month and increace in the other months from the lactation stage. And the acidity of Shami goats milk was high and intensity in the early of lactation stage.
The composition of Shami goat milk proteins was determined and separated (Casein-serum proteins) using electrophoresis technique, and molecular weights was determined comparing to commercial Marker and milk cow. The β-casein of Shami goat milk was the dominant part of Casein proteins and was the fastest in the deportation, compared with β-casein protein of cow milk and had less molecularly weight 23.900 kDa while 26.600 kDa for cow’s milk, and protein αs-casein of Shami goat milk was faster in deportation as compared with that of milk cow and less molecularly weight (30.200- 32.600 kDa) respectively. β-lactoglobulin protein formed proportion (44%) of the total serum proteins of Shami goat milk and was deported faster compared with cow milk, and therefore disagreed in molecular weight (18.80- 18.40 kDa), respectively, and α-lactalbumin deportation did not differ from those of cow milk ( 14.200 kDa ). The amino acids were separated using Amino Acids Analayzer device, the effect of milking season on the concentration of each of proteins and amino acids milk was studied. It was found high proportionS of the total nitrogen and non protein nitrogen and non Casein nitrogen and serum proteins in Shami goat milk compared with cow milk, and high content of essential amino acids (Leucine, lysine, valine and arginine) and non-essential amino acids (glutamat , Brolin and taurine), and did not contain the amino acid basic tryptophan, and observed no significant difference between the concentration of amino acids when compared to reference with cow’s milk, the amino acid cystine Shami was double amount goat milk compared to cow’s milk, and the effect of milking season in each of the proteins and amino acids for milk was unclear largely due to a combination of other factors, the study confirmed that Shami goat milk was an important source of proteins and acids amino when compared with other types milk .
We separated and identify 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 triglycerides results showed no signifiant differences at P≤ 0.01 in means of concentrations of TAG during the lactation and the TAG contents increased with carbon atoms number reached to maximum level of 13% of total TAG for each of C38, C40, and C42. Beyond this point, the TAG of goat milk decreased with the carbon atoms number and reached to the lowest value for C54 at 2%. This gave the fat of goat’s milk distinctive genetic fingerprint for other species. Further were the composition of fatty acids of Shami goats milk fat was isolated and identify during lactation using (GC). The results confirmed that the goat milk fat contained a higher proportion of the following fatty acids: (Cabreuec, Cabrelic, Cubric, of Luric), and medium and short-chain saturated Fatty acids compared with cow’s milk. It contained a higher proportion of fatty acid linoleic, while contained less Butric acid than the cow’s milk fat. The results showed that there were no significant changes in fatty acids of goat milk fat during lactation. The atomic absorption was used to determine the concentration of mineral elements, The results showed high nutritional value of milk Shami goats, due to the high content of important calcium, phosphorus, magnesium, iron, zinc and manganese, compared with cow’s milk mineral elements. The study also confirmed the effect of the process of lactation on the concentration of metallic elements during different months.