Testing the edibility of Caragana Arborescens/Siberian pea tree

Should be said that these plants are a highly dispersive invasive in North America.

William Bronson wrote:Mine are in their dry stage, the pods are all brown.
I will be propagating them this year, but I'm watching your experiment with great interest.

If you have chickens, they will really like them.
https://emptynesthomesteading.com/2022/04/07/chicken-food-for-thought-siberian-pea-tree/
There are even mentions in several articles that in Siberia, peasants used it during the war [WWII] to overwinter their flock.
This leads me to think that it is not a gourmet crop but if cooked it will provide nourishment. I have not tried it, so I will believe what others say about edibility.
Seeing this, though, I am tempted to get s few bushes.
It also seems to have promises as a medicinal plant for female cancers. It will also make a nice hedge...
https://pfaf.org/user/plant.aspx?LatinName=Caragana+arborescens#:~:text=Both%20the%20seed%20and%20seed,Shelterbelt%3B%20Soil%20stabilization%3B%20Hedge
.

To pick up on the antinutrient thread, though this is about the foliage and not the seeds: I fed my rabbit herd large quantities of caragana leaves and stems run through a chipper over a period of about six months. They were clearly highly palatable because the rabbits ate them enthusiastically in preference to the grass hay that was always available. Young rabbits grew well on this diet. The downside was that there were no births after the first month of feeding caragana foliage. Either conception was prevented or litters were aborted very early in development leaving no trace in the enclosure.

Conclusion: I would only feed caragana to young rabbits being grown out for meat. I wouldn't feed any again to breeding stock, or feed it as tree hay (which had originally been my intention).

I know nothing about Caravans beans, but I do know that horse chestnuts are

A) not edible with any amount of processing (correct me if I'm at all wrong, because they grow near me in abundance)
B) usable as laundry soap - the instructions I saw were to soak, blend somewhat, drain and use the liquid.

Kirsty Pollock wrote:I know nothing about Caravans beans, .

Caragana! Damn you autocorrect!

I love this thread and will post some thoughts and experament and experiences at some point.  This plant is amazing! IMO.

Kirsty Pollock wrote:I know nothing about Caravans beans, but I do know that horse chestnuts are
A) not edible with any amount of processing (correct me if I'm at all wrong, because they grow near me in abundance)
B) usable as laundry soap - the instructions I saw were to soak, blend somewhat, drain and use the liquid.

Wow! soap out of horse chestnuts! I had to check that out. It turns out that you can. I was floored. Not for really badly stained clothes but for regular grime. Here is how:
https://zerowastechef.com/2016/10/05/horse-chestnut-laundry-soap/#:~:text=Chestnuts%20can%20be%20pulverized%20using,your%20next%20load%20of%20laundry.

My understanding is that horse chestnuts have been traditionally used as famine food after being ground and then given a long soak in running water, as with acorns but longer.

Ellen Lewis wrote:My understanding is that horse chestnuts have been traditionally used as famine food after being ground and then given a long soak in running water, as with acorns but longer.

They are, however poisonous:
https://www.poison.org/articles/horse-chestnuts-are-toxic-214#:~:text=Horse%20chestnuts%20contain%20a%20toxin,common%20symptom%20is%20stomach%20irritation.
The poison they contain is saponin aesculin. I have no doubt that in periods of famine, humans have attempted to eat them:
In 1870, in France, there was a terrible famine, with many in the countryside dying. In Paris, they even attacked a zoo and killed some animals. A restaurateur even cooked part of an elephant's trunk. https://www.mentalfloss.com/posts/paris-siege-eating-zoo-animals
Just to tell you that in a famine situation, people will eat anything. John Weiland, on a permies thread speaks about it:
https://permies.com/t/58996/Reducing-eliminating-toxicity-horse-chestnut
You mentioned acorns. Acorns are not poisonous but by soaking them several times, you remove the tannic acid, which make the acorns taste so bitter.
I would not try it, and if I were starving I would cook it... a lot... and eat maybe one or two, but I had better find something else to make bulk, like grass, bark, sewer rats which were also eaten in that year...
In France during WWII many people had very little to eat and everything was rationed. The only available vegetable they had in abundance was sunchoke [AKA Jerusalem artichokes. The Germans fed sunchokes to their pigs].
After the war, my dad would never eat it, to his dying days.

Seems several toxins are found in legumes. Cytisin in Laburnum, wisterin in Wisteria. If a plant's going to invest energy in its seeds, it'll want those seeds to survive, not be eaten (unless the idea is to produce so many that some get away - eg grasses, or some foraging helps to disperse the rest - eg acorns).
The amount of toxin will vary between individual plants, and by careful selection strains should be able to be bred that are safe.
First we need a quick, preferably low-tech, way to determine the canavanine content.

I wonder if adding a little ACV to the soaking water would help as well. I do this when I’m soaking things but dont have enough time to do the recommended length of soak.

I havent tried eating any of them myself yet. I have some from this fall that I intended on feeding to the chickens but haven’t done that either. Maybe Ill try that this weekend.

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

Louis-Philippe Bonhomme-Beaulieu wrote:Hi all,

I know this is an old thread, but I would like to draw your attention to some scientific studies that suggest that peas from the Siberian Pea shrubs (Caragana arborescens) may not be the best legume to add to your plate as a staple food.

Firstly, the peas from the Siberian Pea shrub contain a significant amount of the toxic amino acid arginine analogue L-Canavanine, according to the following article:

"Colutea arborescens, Caragana arborescens, Vicia gigantea, Robinia pseudoacacia and Wisteria floribunda, representative of many prolific canavanine producers, store from nearly 6 to 13% canavanine by dry weight" -- L-Canavanine: a higher plant insecticidal allelochemical, Amino Acids. 2001;21(3):319-30. doi: 10.1007/s007260170017, temporary link to the content of this article.

Secondly, this interesting article investigated the death of Chris McCandless in 1992 established the possibility of L-Canavanine toxicity, which was likely exacerbated by McCandless's state of malnutrition. Also, it describes reports of symptoms similar to systemic lupus erythematosus in monkeys and humans that consumed L-Canavanine in low concentrations (2 wt% of diet for the monkeys). -- Presence of L-Canavanine in Hedysarum alpinum Seeds
and Its Potential Role in the Death of Chris McCandless, Wilderness & Environmental Medicine. 2015;26:36-42.

I hope these articles provide food for thought!

this is the scientific paper, i wonder if heat destroys L-canavanine in this bean? i would like to feed these seeds to my hens:

Abstract
Objective: For the past 2 decades there has been vigorous disagreement over the purported toxicity of Hedysarum alpinum seeds, and whether the consumption of such seeds was a factor in the 1992 death of Chris McCandless, the subject of the book Into the Wild. Our objective was to confirm or disprove the presence of L-canavanine (a nonprotein amino acid known to induce systemic lupuslike symptoms in humans) in H alpinum seeds.

Methods: Liquid chromatography-tandem mass spectrometry analysis of H alpinum seeds was performed.

Results: Our analysis confirmed the presence of L-canavanine in H alpinum seeds and demonstrated that it is a significant component of the seeds, with a concentration of 1.2% (weight/weight), roughly half of that found in Canavalia ensiformis.

Conclusions: The data led us to conclude it is highly likely that the consumption of H alpinum seeds contributed to the death of Chris McCandless.

Keywords: Hedysarum alpinum; Hedysarum mackenzii; Into the Wild; L-canavanine; McCandless; ODAP.

I've been reading up on this as it does look like a very useful plant. Canavanine works as a toxin by displacing the amino acid arginine and this creates abnormal proteins which interfere with a lot of very necessary enzyme processes. If someone is malnourished and eats a lot of canavanine containing plants, it could be highly toxic. For someone eating a healthy varied diet containing plenty of arginine (found in animal products, dairy, and highest in pumpkin seeds), I can't find anything suggesting a moderate intake of canavanine would be harmful.

There doesn't actually seem to be a reliable source regarding canavanine content of Caragana seeds, just the one article that doesn't give a source for the statement. The article that is the possible source, dating to 1967, is unfortunately behind a paywall so can't be accessed. There is good evidence for substantial levels of canavanine in alfalfa sprouts, by the way, a commonly available food I've eaten loads of in the past!

I think provided the seeds were soaked then boiled, as with any dried beans, I'd be happy to eat Caragana arborescens seeds. Just need to plant some! It does grow in Bulgaria and isn't listed as invasive there.