Heating whey protein: Question for James or anyone in the know

I like to use whey to make my own protein bars and I was looking for some recipes and I came across this thread.

http://www.nzbodybuilding.co.nz/viewtopic.php?f=11&t=1202&start=0

'Heating whey protein does actually change the amino acids causing cysteine to convert to cystine. Cysteine is a glutathione precursor which is very important for your immune system. Cystine is not that important.

Heat also denatures whey by damaging the protein fractions - GMP's, BSA, IgG's, ect
These microfractions are what sets whey protein apart from other protein sources and by damaging these you nullify much of the benefit of using whey protein. Because of this denaturing of the protein fractions the BV or bioavailability will be reduced lowering the amount of usable protein you absorb.

I wouldn't recommend baking with whey, or heating to high temperatures for any length of time.'

Does anyone who knows about this stuff share there thoughts ? Would I be better off not using whey for cooking?

because I do not hate you, unlike James, and because I am bored
 
heating denatures the tertiary and quaternery structures of proteins, for the most part it does not affect secondary or primary. so for the most part any potential biological aspect of the protein will be reduced. ALL food proteins go through a structural change when being cooked. egg protein, sure dont look the same after its been cooked, denatured. chicken, yummy when raw, but far better when cooked, denatured. Cooking that bread, baking that pie, making cheese all involve denaturing the proteins.

denaturing by itself is not bad, in some cases it can increase bioavailability, in other cases, usually extreme, it can reduce bioavilability. cook that steak until its a burnt pile of garbage and you wont take much up

the cysteine/cystine thing shows that the person doesnt really have much of an idea of what they are talking about.

cysteine is a sulphur containing amino acid, Cystine is the oxidised dimeric (2 units) form of Cysteine, held together by a disulphide bond. within dairy they are commonly combined within the analytical techniques, and both are present within milk, and heating can break the disulphide bond in cystine to release Cysteine...

Cystine is not that important?

Glutathione is a cool part of the anti-oxidant system. formed from Glycine, Cysteine and Glutamine.

in the extracellular fluid, Cysteine auto-oxidises to cystine, where as once taken up by the cells cystine is rapidly reduced to cysteine.

so it doesnt matter if some is intra-converted, as the body knows what to do with it no matter what. and to say that Cystine is not important is to say taht cysteine is not important.

denaturing of the bioactive proteins.

whey has a bunch of bioactive proteins, Immunoglobulins, bovine serum albumin, lactoferrin and glycomacropeptide from Kappa-casein. The problem with saying these protiens are biologically active is that 1) we are not babies and 2) we digest (denature) the proteins no matter what.

now if you believe the biologicals to have an effect, then not cooking may be fine, if you are just using whey as a source of amino acids then who cares.
it doesnt really do a lot to the BV of the protein. but oh well.

Yes, that's better that I could ever say, so what he said!

(PS I don't hate you!)