The content of triacylglycerol and cholesterol in milk of different species

Abstract

Today, dairy products are a significant part of falsified food. Of all types of falsifications, it is most difficult to establish intermodal substitution. There are cases of dilution of sheep and goat milk to cow. The most accurate test for the species of milk and dairy products is the polymerase chain reaction. However, this method is expensive and time-consuming. Proceeding from this, the aim of this work was to determine the concentration of total cholesterol and triacylglycerol in milk of cows, sheep and goats, which in the future can be used as the theoretical basis for the creation of informative diagnostic tests for interspecific milk falsification. For research, 7 samples of milk from cows, sheep and goats were selected. In the test samples, the content of triacylglycerol and total cholesterol was determined. The test system “Philitis-Diagnostics” was used. The obtained digital material indicates that the highest level of triacylglycerol is recorded in the milk of sheep, and the lowest – cows. Thus, in sheep's milk, the level of triacylglycerol was 3.4 times higher (P < 0.01), compared with milk of cows, and 1.5 times as compared with milk of goats. In milk of cows, this indicator was 2.2 times lower than that of goat meat. The level of total cholesterol in sheep's milk was higher by 5.7 times (P < 0.01), compared with milk of goats and 4.5 times (P < 0.01) with milk of cows. Its level in milk of cows was higher by 1.2 times, compared with the content of goats milk. The statistical analysis of the results showed a strong negative correlation between the total cholesterol and triacylglycerol content in goat's milk (r = -0.7) and sheep (r = -0.8). In milk of cows such correlation dependence is not established (r = 0.4). It should be noted that significant individual variations of the studied parameters within a single species of animals. This may be due to the season of the year, feeding, the period of lactation, the age of the animal, the state of the health of the mammary gland, as indicated by other researchers. It has been established that the level of total cholesterol and triacylglycerol in animal milk is unstable. However, the level of triacylglycerol in sheep's milk is significantly higher than in milk of cows and goats, and the level of total cholesterol is lower in milk of goats compared with milk from cows and sheep. Such results suggest the promising use of triacylglycerol and total cholesterol in animal milk as an informative complement to existing interspecific falsification tests. In further studies, attention will be focused on the peculiarities of the fractional composition of milk lipids and the study of the level of triacylglycerol and total cholesterol in products made from falsified and unfertilized milk.