"Chemical agents" — ... Sure it sounds scary if you say it that way, but I prefer the more standardized term of "baking soda."
Humans have been using baking soda for millennia.
(I don't know about the gluten thing, but I know it's the in thing to claim non-celiac disease gluten sensitivity but it is not supported by evidence and, in fact, generally disproven by evidence. I harbor doubts that they've actually increased gluten that much, but even if they have, you're likely barking up a wrong tree there too.)
Actually, the biggest thing I've heard of in regards to this stuff which I suspect is more likely is that more of the actual hulls/etc get separated out now instead of ground in. This is generally easier, but it is also a bit less healthy in many ways.