Study of Fatty-acid Composition of Goat and Sheep Milk and Its Transformation in the Production of Yogurt

Abstract

The information on the structure of fatty acids is crucial for the production and promotion of goat and sheep milk in the manufacture of dairy products. The fatty-acid profile of milk fat can affect the nutritional value and market value of dairy products. The purpose of the research is to study the properties of fatty-acid composition of goat and sheep milk and its transformation in the process of yogurt production. The study of fatty-acid composition was performed using the method of gas chromatography. The milk of goats of Zaanen breed and sheep of North Caucasian breed, as well as yogurt produced from a mixture of goat and sheep milk in a ratio of 1:1 have become the objects of the study. It was found that goat’s milk contains 12% less saturated fatty acids than sheep’s milk. Oleic, stearic and palmitic acids are the main fatty acids found in the fat phase of milk and yogurt production. Changes in the concentration of individual fatty acids during milk processing and in the period of yogurt storage were noted. As a result of maturation and seven-day storage, the amount of saturated fatty acids in yogurt increased by 5% compared to the original milk mixture. The content of polyunsaturated fatty acids in yogurt decreased by 19.27 %. The highest ratio value of hypocholesterolemic and hypercholesterolemic fatty acids was noted in goat milk. It is proved that goat milk is characterized by the most acceptable fatty acid composition in terms of healthy nutrition and prevention of atherosclerosis and thrombosis. A tendency to reduce the amount of monounsaturated and polyunsaturated fatty acids, with a simultaneous increase in the content of saturated fatty acids is noted in the process of yogurt production and storage. It was found that the production of yogurt with the use of goat’s milk in the mixture allows reducing the values of atherogenicity and thrombogenicity indices. The results of the study provide an information basis for the production of qualitatively new fermented milk drinks with a fatty-acid profile favorable for human health.