Quote:
Originally Posted by Bisons
Heat treating milk does not suddenly and magically turn the casein protein in milk to whey or whatever. It's still casein and digests slowly.... honestly where did you hear that?
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Heat treatment DOES turn a lot of things into other things. Call it magic if you want, but when I heat treat a pan of water for long enough, I got an empty pan
Reagrdless, I remember reading on the label of some supplements that casein had to be filtered off Milk using rather expensive techniques which justified the ridiculous price asked for 100% casein powder compared to whey which is a concentrate. Most proteins are seriously altered by temperature or acidity levels. I give you an example: eggs. Raw it's liquid-ish, you boil it for 5 min, it's solid, and there is no way to turn it back to liquid (it's called coagulation).
After some time on google, it appears that the pasteurization of the milk does not generate temperature sufficient enough to alter casein, hence it seems that my earlier statement might have been misguided, or that this particular label was only there to justify the exorbitant price asked for caseinate supplements.
In the mean time, it is important to consider that the most common form of protein supplements is made of whey proteins, which are more commonly known as protein concentrates, and are NOT slow digesting, yet far more readily available than caseinate. Add to this the fact that 80% of proteins found in raw milk are caseinates, it seems hard to understand that the potential 20% remaining only are fast digesting, concentrates, and yet cost 1/2 as much as caseinates, and are at least 10 times more common. There is a certain lack of logic in there... And I tend to be a very logical person, hence my earlier statement: if heat treatments alter proteins and pasteurization/uht/boiling are heat treatments, it seemed logical that they'd alter the casein. Now, if the temperatures involved do not, my bad... (boiling DEFINATELY does).
Now, you seem to have some misunderstanding about whey, and how it is obtained. Whey is a by-produt of the milk... it's only the watery part that is left after coagulation and removal of the curd (this go to make cheese). Whey is not a protein, but the 'whey protein' are proteins extracted from whey. These proteins, as concentrates, are NOT, as mentionned above, slow digesting, and are not casein. The curding process usually involve the use of heat, acid or rennet (enzymes). As I write this, I start to understand... Casein does coagulate in acidic environment (for example in the stomac, which is why it makes for slow digestion of the amno acids it contains). So the casein is gone off to make cheese, and there isn't any left in the whey... It also explains the economics, whey used to be dumped in the river in the old days (pre second world war cheese maker can easily support this), whereas wasting milk to make protein powder instead of cheese, that's a waste
(any French or Dutch will also support that).
So, in summary, I have been misguided by a label explaining the origin of casein protein and their availability. Although heat treatments does magical wonders (like hardening an egg or emptying a pan), it may not have sufficient adverse effect on pasteurized milk. the same may also be true of UHT, though the temperatures involved are much greater. Boiling milk will alter its proteins however.
Interesting discussion non the less.
Further reading (and a litle about casein de-naturation while pasteurising) :
1.
Milk: the pros and cons of processing
2.
A Special Report from The Association of Unpasteurised Milk Producers and Consumers