Does organic or grass-fed matter?
First, let’s deal with that organic certification you might see on a whey protein powder. It means that the cow was given neither hormones or antibiotics, and that its pasture or feed was itself organic. Does that make your powder healthier? Maybe, maybe not: while there is some evidence that organic produce might be safer, whey protein is very different from a salad. All we can tell is that there doesn’t appear to be any difference in the whey protein composition of the milk produced by two farms, one certified organic and the other not, that have similar farming practices.
But what about when the farming practices differ?
An increasing number of companies advertise that they source their whey from cows raised on pasture or fed grass rather than grain. There are important environmental and ethical arguments to be made about either practice, but our focus here will be on its effect on the nutritional value of whey protein.
This effect is, at best, minimal. An early study reported that greater access to pasture resulted in small increases in some whey bioactive peptides, but small decreases in others, whereas a later study found no meaningful differences.
There is little nutritional difference between whey protein sourced from the milk of cows raised conventionally and whey protein sourced from the milk of cows pastured or grass fed. Also, an organic certification has no impact on whey protein composition.
Does pasteurization denature whey?
The FDA requires that all milk intended for human consumption be pasteurized, including any used to make whey protein powders. So all whey protein powders are pasteurized at least once, meaning there is no such thing as raw whey protein powder.
The most common type of pasteurization in the dairy industry is high-temperature, short- time (HTST) pasteurization, in which milk is heated at 72C (161F) for 15 seconds and then cooled rapidly. Basically, milk is run through millimeter-wide, superheated tubes for 15 seconds, then through supercooled tubes to end the pasteurization process nearly instantly. HTST pasteurization does not denature whey protein,which is why it is used notably in the production of a patented, non-denatured whey protein powder.
A less common form of pasteurization, called vat or low-heat pasteurization, involves heating large batches of milk to 63C (145F) and holding them at that temperature for 30 minutes. Some companies may advertise the use of this type of pasteurization because it uses lower temperatures than HTST pasteurization. Over time, however, this “low” heat is still high enough to denature several whey protein subfractions, especially when we consider that the exposure time is not just the 30-minute holding temperature but also the time it takes to heat and cool the vat of milk. Some studies have reported that 10–20% of whey proteins are denatured during vat pasteurization.