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answerman
-1
Votes
answerman  |  January 08, 2009 07:04 PM
Lots of casein, which is a white salt of calcium.
Comment
mrgunn
mrgunn  |  January 10, 2009 04:02 AM - Fact Refuted
The color doesn't have anything to do with casein specifically, but with light-scattering in general. Also, casein is a protein, so it's not correct to call it a calcium salt.
answerman
answerman  |  January 10, 2009 04:28 AM
"The color doesn't have anything to do with casein specifically, but with light-scattering in general"


Uhhh.... wat? That's as silly as saying that the yellow color of gold has nothing to do with gold itself and is wholly due to light. Obviously, the color is reliant on both the light and the structure of the material being viewed. Since light is a given in this discussion about the visible color of some object, it's quite a lot more relevant to discuss the structures which are affecting the light.
answerman
answerman  |  January 10, 2009 04:33 AM
"it's not correct to call it a calcium salt"

@mrgunn:
Casein exists in milk as the calcium salt, calcium caseinate.
http://www.chemistry.mcmaster.ca/~chem2o6/labmanual/expt11/2o6exp11.html
ledretch
both are right! : )
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Comment
tracebooks
3
Votes
tracebooks  |  January 08, 2009 07:24 PM
Real milk isn't white. It's sort of a creamy very pale yellow because of the vitamins and other nutrients. A lot of that is destroyed in processing, so they add back in powdered milk to give it body. It also has the effect of making it whiter.

This is a very good video, but I can't post it because they disabled embedding. It's very good:

http://uk.youtube.com/watch?v=Yr5pl6lgjJ8
Comment
marcel m
3
Votes
marcel m  |  January 08, 2009 07:26 PM
Well it is my understanding that milk is mostly white due to the fact that it contains copious amounts of Calcium Phosphate. From a physical optics point of view the reason is ,"That the whiteness is due to the scattering of light by the colloidal particles of the milk emulsion. Just the fact that we get white shows that there is no absorption, so whatever is there is transparent i.e the casein which contains the Calcium Carbonate.
Another notable factor is the fact that ,nearly all whites are the result of scattering from colloidal-sized particles,they you have it that is why we perceive the color of milk as white akin to a surface that reflects back all the light shone on it much like the white pigment titanium dioxide which is made of clear crystals, dispersed as colloidal particles.Now there you have it,I hope that was a helpful answer.
Comment
easyeboy
-1
Votes
easyeboy  |  January 08, 2009 08:06 PM
Those chalky-white mustaches that color our lips after chugging down a refreshing ice-cold glass of creamy milk is caused by the protein called Casein.

Rich in calcium, Casein helps contribute to milk's white color.

In addition, the cream that is found in milk contains white colored fat. The more cream in milk the more white it is.

Low and non-fat milk appear more grayish rather than white because they contain less cream.

Another reason milk looks white to our naked eyes is because some objects do not absorb very much light. Rather than absorb light, these objects reflect light. For instance, red colored objects reflect only red light and absorb the other colors of light in the rainbow spectrum. The molecules that make up Casein and cream reflect light. That's why milk is white.
Comment
mrgunn
mrgunn  |  January 10, 2009 03:58 AM - Fact Refuted
Milkfat is actually off-white, as anyone who has made their own butter knows.
Also, the color doesn't have anything to do with casein specifically, but with light-scattering in general.
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