Effects of homogenization and heat treatment on fatty acids in milk from five dairy species

Milk fatty acids significantly contribute to human nutrition and clinical health. However, previous evidence for changes in the fatty acid profiles of different dairy species following homogenization and heat treatment is lacking. Here, changes in fat globule particle size and fatty acids in samples of Holstein, goat, buffalo, yak, and camel milk following homogenization (20 MPa) and heat treatment (63 °C for 30 min and 90 °C for 15 min) were investigated using a laser particle sizer and gas chromatography approach. The results indicated that the milk fat globule particle size of all studied dairy species significantly decreased after homogenization and heat treatment, in which there was no difference. The fatty acid composition of C10:0 and medium-chain fatty acid in goat milk, C18:0 and long-chain fatty acid in camel milk, and C16:0 in buffalo and yak milk served as the characteristic traits of these milks. Changes in the relative contents of several fatty acids (C4:0, C10:0, C16:0, C18:0, C18:1n9c, and C18:3n3) were dependent on homogenization, heat treatment, and the type of dairy species. In particular, C18:3n3 significantly decreased in goat and camel milk after homogenization and heat treatment. These findings provide new insights into how homogenization and heat treatment affect the fatty acid profile and can be used to further improve the heat treatment of milk from minor dairy species.