|MadSci Network: Zoology|
Hi Thomas, A simple answer to your question is that as far as I know (and I did check with other faculty in our department), all milk is white. The shades of white will vary depending upon the composition. Factors that contribute to the color of milk are fat, dispersed cassein (one of the classes of milk proteins) and calcium complexes, and water-soluble riboflavin (a vitamin). These compounds contribute to milk's opaque ivory color by interfering with light transmission. The ammount of carotene in the diet will also affect the color. They provide a yellowish color. High concentrations of ribolfalvin also contribute to the yellow color. Removal of the fat and thus carotenoid pigments and solids when making skim milk accounts for the bluish hue one sees with this product. Thus, one would expect milk from mammals with a high fat content (marine mammals) to have a yellower tinge. I hope this answers your question. Al Bushway Professor of Food Science
Try the links in the MadSci Library for more information on Zoology.