We’re currently working on this area. We’ve just come back from Australia where we have acquired a sample claiming to be 100% Gluten flour (even though it is only 89% Protean).
Initial tests show that we are able to estimate the overall level of protean in a variety of wheat flours. Flours claiming to be gluten free are, of course, not made from wheat. We’re going to try adding them into the collection and see if we can build a model to distinguish. Any scientific input on this most welcome.