Usage of Hazelnut shell flour in food and feed industry

The shells Looks useful as antioxidants extractive for functional food industry .
https://www.mdpi.com/2304-8158/10/6/1197/htm

In which country is this produced the most?

Turkey. Almost all hazelnut shells used as fuel. I am trying to find new ways to recycle them.

With sustainability matters going around, there is a need convert every food waste to useful food products.
Hazel nut shell seems a very hard material and considering all functional food preparation also, this could be a tough choice.
Even today BSG, Okara are still facing its own challenges and additionally comes the waste from plants, fruits (seeds, peels), nut shells and so on.
At least we could look at it as degradables compared to plastics!!

I searched a lot but could not find any regulation about this type raw materials.

Does anybody have any experince?

need some applied research