Abstract: In this paper, milk samples with different fat contents (0.5%, 1.5%, 2.5% and 3.5%) (n = 12 for each fat content) were prepared and comparatively tested for their chemical composition, microstructure, particle size, color and stability. The results indicated that both the casein and total solid contents of milk were significantly increased (P < 0.05) with the increase of fat content. Yet, there was no significant difference (P > 0.05) in protein content among milk samples. The acidity of fresh milk samples was in the range of 16–18 °T, which was directly proportional?to fat content. In addition, the higher the amount of fat was, the less stable and more yellowish the milk system became. Hopefully, this study will provide basic data for exploring the relationship between fat content and physicochemical properties of milk, and provide a technical basis for the development and production process optimization of dairy products.

Key words: milk, fat content, particle size, color, stability