Thank you for this, I've actually never come across this term(or if I have I never found it important enough to remember ), but I'll read up
And about the second bit, even by these PDCAAS readings, whey and animal sources are still better than soya etc right? Exactly what I was saying. Or did you mean something different...?
Alright so I found out the deal behind the 'gold standard' that is PDCAAS. The BV had been in existence since a long time and rated proteins on the basis of their usefulness in diet, specifically in the sense of how fast something was absorbed and how much of the EAAs it could provide for the body. Just like glucose is the comparing standard for all sugars(when we compare carbs in the GI index, we compare it with glucose which has max value of 100), similarly BV ratings put Eggs as the highest standard and gave it the top value of 100. All other proteins were compared w.r.t Egg. Then Whey came into the picture. But whey was not only faster absorbing, but depending on the combination, provided even more EAAs. Hence they rated Whey off the scale at a level of 104. All veg proteins were second graded and not even comparable to the First class sources, specially amongst the heaviest users(athletes). This upset the Soy lobby. The Soy lobby brought in a new standard of comparison which favoured them graciously. In PDCAAS both Eggs and Soy are labeled at 1.0 peak value. That's like comparing an Ambassador to a Formula F1 car, with the speedometer limit fixed to 60kmph. Since both can reach the speed limit, they both are considered equal.
"This is in sharp contrast to the original & most effective protein rating system which is Biological value (Bio-availability) which gives a score of 100 to Eggs & 69 to Soy & 104 to Whey.
The whole concept of 1st class protein started from the Biological value of foods...The PDCAAS was not even needed as an alternative rating system. Since the Soy lobby could not prove equality with Egg or whey or the animal meats...it came out with its own convoluted system."
Besides all the political protein wars, the most significant fact is that Soy is deficient in Methionine.
Thanks for bringing up PDCAAS by the way, I learnt something new!