somewhat interesting

[Admin]

Alright so basically some guy from reddit who owns a biology lab offered to test the contents of protein powders to check how much we are being lied to.

This is the thread where the guy explains everything. Offering broscience service: I'll test your protein powders : Fitness

And these are the results
https://docs.google.com/spreadsheet...nR0WVZybGtFWnRKNzdKNm9XOVE&toomany=true#gid=0


THOUGHTS?

Edit: Also found this where the test originated from. American Pure Whey is American Pure Shit : Fitness I can't emphasise how much of a good read that is. Amazing

 

[walt]

where did you find this link

 

[Admin]

it got sent to me via email , just thought it would share

 

[chocchillimango]

definitely interesting. I wonder if anyone has taken on the chance to cross check his findings.

bit of a worry for devotees for some of these brands.

 

[oldcorollas]

bad for some... but will always be some difference between dry % and packed %
Professional Whey say for their WPI "91.6% dry basis, 88% as is..

even if the guy was not doing accurately, there is too big a range to be experimental error... ?

but seems odd that "american pure whey" has only 1% protein??
the rice protein was also 6% instead of 80%...

I do stuff like this sometimes (running semi-public tests of stuff at work, on metal, not protein) but it always comes with the caveat of "if you want real results, take it to real lab"
maybe his tests were not appropriate for checking content of all the different protein types?

a few links abotu his 280nm UV absorbance test
Measurement of protein concentration using absorbance at 280 nm
Protein Assay using UV-Spectrophotometer at 280 nm

and a more comprehensive
http://www.nihs.go.jp/dbcb/Bio-Topic/protein.pdf

I have a photospectrometer at work, but usually for infrared spectrum..
there is a UV/visible light one as well, but is busted
both of them are for solid materials, rather than liquid samples..

anyone got a UV photospec that can do liquids?

 

[oldcorollas]

Tryptophan and tyrosine absorb ultraviolet light strongly at 280 nm. The tryptophan and tyrosine content of many proteins remains fairly constant, and so the absorbance of protein solutions at 280nm can be used to determine their concentration

the accuracy can be greatly affected by the different proteins present..
Peptide and Amino Acid Quantification Using UV Fluorescence in Synergy HT Multi-Mode Microplate Reader
since they don't all have absorption peaks at 280nm
phenylanine is more like 255nm, and doesn't absorb much at 280nm..

per 100g protein, my PW WPI has 0.9 Tryp, 2.5 Tyr and 3 phenyl..

anyway.. 280nm test is quick and easy but not necessarily acurate when you are talking abotu different protein combinations...

edit: it would be really interesting to do the same with each type of protein commonly found in products