Thanks Myron and Kate for volunteering
I ordered a shrub today to finally try it out and so started to investigate.
In case you missed it, Melissa Hofmann posted a link in another
thread to her experiments with Siberian Peas, making Miso / Tamari – and it seems she updated it with another experiment: Making tempeh with soy and Siberian Peas¹.
Regarding the L-Canavanine, which might be partly removed by soaking already, fermenting it with Rhizopus oligosporus (aka making tempeh) could further reduce it or maybe almost completely remove it. The fungus modifies not only sugars but also proteins². To be honest, how L-Canavanine affects the body doesn't sound like you want that. But also I only found one source that actually claimed there is L-Canavanine included. So to me that's still to be clarified.
Given that the shrub is an excellent pioneer and soil building species, among many other benefits, and is perennial, I think it would be great to make it a serious source of food. If you think about it, there are lupins in the same family, which have been bred to be non toxic. Today you can buy processed food products from sweet lupin in almost every organic shop in Germany. Also the seed size and ease of harvesting can be improved through breeding.
Links:
[1] https://shofarm.com/blog/perennial-miso-siberian-peashrub-caragana-arborescens[2] https://en.wikipedia.org/wiki/Rhizopus_oligosporus
