I ran across a post by Julia Vins, a powerlifter, comparing two brands of whey protein powder.
The original text is in Russian:
Решила сегодня сравнить whey gold standard от optimum nutrition и whey protein от pureprotein банальным способом - залив кипятком. Этот метод указывает на отсутствие или наоборот присутствие белка. Для большей убедительности взяла даже одинаковые вкусы :) Pureprotein: растворился в горячей воде даже лучше, чем в холодной. Меня это немного удивило, и, начитавшись информации о подобных тестах, я решила его сварить. Но, увы, и этот тест меня разочаровал. Растворился всё также идеально, и в течении пяти минут варки так и не свернулся в комочки. Whey gold: совсем другая ситуация, свернулся практически полностью после добавления кипятка. При варке образовал плотные сгустки. Я думаю, комментарии тут излишни. Цена соответствует качеству, как и должно быть :)
The Google translation:
I decided today to compare whey gold standard of optimum nutrition and whey protein from pureprotein banal way - Gulf of boiling water. This method indicates the absence or presence of the protein contrary. For more convincing, even took the same tastes :) Pureprotein: soluble in hot water, even better than in cold. I was a little surprised by this, and, having read the information about these tests, I decided to cook it. But, alas, this test has disappointed me. The solution is also perfect everything, and within five minutes of cooking never curled into lumps. Whey gold: a completely different situation, curled up almost completely after the addition of boiling water. When cooking has formed dense clumps. I think that comment is superfluous. The price matches the quality, as it should be :)
Google tends to botch Russian translations, so I'm trying to make sense of Julia's point. In the last sentence, she's concluding that "you get what you pay for". Optimum Gold Standard is more expensive than PureProtein by an average of 20 cents per ounce. Thus, in her eyes, Optimum is the higher quality protein. And since the only difference is that Optimum doesn't dissolve well in cold water and even curdles in hot water, then insolubility is proportional to quality of the protein. I understand her experiment, but not the premise. How does solubility of whey protein correlate to its effectiveness?
