Authors
Title
Abstract
Cows of three cow breeds: Polish Holstein-Friesian black-white variety; Polish Holstein-Friesian, redwhite variety and Polish Red were milked and the milk was centrifuged to separate the fat in the form of sweet cream. Next, the sweet cream was inoculated with butter milk starter and, after the incubation, a cream was produced. In the products produced, the following was determined: the content of fat using a buthyrometric method; the content of cholesterol using an enzymatic method with cholesterol oxydase; the fatty acid profile using a gas chromatography method; and the diameter of fatty globules using a microscopic method. It was found that the milk from cows of three cow breeds differed statistically significantly (p ≤ 0.01) in the content of fatty acids: C15:0, C16:0, C18:0, C18:1n7, CLA, C20:0, C4:0, C14:0, C14:1, C17:0, and C18:3n6. The cow breed had no effect on the content of the following acids: C6:0, C8:0, C10:0, C12:0, C18:2n6, C18:3n3, and C20:1. The fat in milk produced by the cows of the Polish Holstein-Friesian breed, black-white variety, was characterized by the highest contents of the following fatty acids: C 16:0, C 18:1n9, C 14:0, C 18:0, and C 12:0. In the fat in milk produced by the cows of the Polish Holstein-Friesian breed, red-white variety, the following acids prevailed: C14:1, C15:0, C18:0, C18:3n6, CLA, C20:0. In the fat in milk produced by the cows of the Polish Red breed, the amounts of the following acids were the highest: C4:0, C 18:1n9, and C 18:1n7. In the fatty acid profiles of milk produced by the cows of the three breeds, the following acids predominated: C16:0, C 18:1n9, and C14:0. No differences were found in the profiles of fatty acids in the fats of milk, sweet cream, and cream; this fact confirms their stability during the centrifugation and pasteurisation of milk as well as during the acidification with starter cultures. It was proved that the milk fat contained lightly more cholesterol compared to sweet cream fat and cream fat. The acidification of sweet cream caused the content of cholesterol therein to decrease almost twice, and this reduction resulted from the activity of starter culture bacteria.
Keywords
milk, sweet cream, cream, cow breed, fatty acid profile, cholesterol, fat globules diameter