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Every now and then, when I pop over to my grandparents' house, they make sure to give me a glass (or two) full of fresh milk (or "whole milk" if you will) and then proceed to pamper me for the rest of the day.

Now, it suddenly struck me that the fresh milk I get over there actually has this really faint yellow tinge, as opposed to the skimmed milk I get at the store which is almost pure white.

I did try Googling this up, but I can't seem to find anything on what imparts the yellow tinge to fresh milk.

So,

What substance/pigment is responsible for the yellow tinge associated with fresh milk?

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  • $\begingroup$ White light scattered in a colloidal medium has slightly different colours depending on the angle to the incident light under which you see it. Mie scattering. If it does not depend on the angle, then it is probably something in the milk. $\endgroup$ – Karl Jan 11 '17 at 17:07
  • $\begingroup$ @Karl " probably something in the milk" Yeah, fat globules ;) $\endgroup$ – paracetamol Jan 11 '17 at 17:48
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    $\begingroup$ See: Butter ... $\endgroup$ – RBarryYoung Jan 11 '17 at 19:40
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    $\begingroup$ You wrote ‘skimmed milk’ but I assume you wanted to write ‘white water’. $\endgroup$ – Jan Jan 11 '17 at 20:29
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The main substances that cause the yellowish color of the milk are carotenoids [1]. The main carotene involved is the beta-carotene coming from the feed that cows eat.

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Some studies have been carried on and it has been noticed that the milk with a more yellow tinge was collected during late spring and early summer when carotene levels are at a maximum [2] unfortunately for this reason in many products as mozzarella they add titanium oxide. The amount of Riboflavin is too little compared to that of beta-carotene and generally gives a slightly green-ish tinge to the milk as reported here and here [3].

  1. P. F. Fox, Fundamentals of Cheese Science,p. 13
  2. Kosikowski, Frank V., and David P. Brown. "Application of titanium dioxide to whiten mozzarella cheese." Journal of Dairy Science 52.7 (1969): 968-970.
  3. Marion Eugene Ensminger,Audrey H. Ensminger,Foods & Nutrition Encyclopedia, 2nd Edition, Volume 1,p. 798
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    $\begingroup$ Also worth noting that carotenoids are fat-soluble, so their concentrations are going to be much much less in skim milk than whole milk. $\endgroup$ – pwcnorthrop Jan 11 '17 at 14:55
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    $\begingroup$ @pwcnorthrop And much higher in butter ... which is why we think of butter as being light yellow. $\endgroup$ – R.M. Jan 11 '17 at 15:23

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