Does lacto-fermentation break down agaritine in Agaricus?
Does lacto-fermentation break down agaritine in Agaricus?
I love the flavor that develops from lacto fermenting mushrooms. I'm a little bit suspicious of white button mushrooms (Agaricus species) since they contain agaritine. Agaritine is broken down by heat, making it safe. If you eat raw Agaricus, the agaritine is made into phenylhydrazines in the gut, which causes liver damage and can eventually make you anemic. Under no circumstances should you eat raw Agaricus.
So what about lacto-fermenting them? We know agaritine is heat sensitive. Is it also sensitive to microbial activity, so that it breaks down?
Short summary from a quick search in the literature: Agaritine in water degrades quickly if oxygen is present, so if you can have an extended amount of time during which the mixture of water and ground mushroom is exposed to fresh air, that will help. As the mixture becomes acidic, degradation speeds up again even if the the atmosphere becomes oxygen poor. If the fermentation is meant to take more than 3 weeks, the acidic environment will probably be enough. Enzymes from the microbes are likely to have a combined effect that ultimately speeds up degradation as well, but that is a more complicated process and so it is not so easy to estimate the rates.
Low pH, exposure to water, oxygen, and time will help. It seems like it degrades quite quickly in water if oxygen is present, but in lacto fermentation you do want to create an anaerobic environment so you might have a quick degradation followed by the formation of a protective atmosphere.
The lowering of the pH will then help speed up the degradation again, but not as much as oxygen does.
Have a look at the following paper to see curves of how agaritine degrades in water in the presence of fresh air, in a closed vial, at different pH levels:
Hajšlová, J., Hajkova, L., Schulzova, V., Frandsen, H., Gry, J., & Andersson, H. C. (2002). Stability of agaritine-a natural toxicant of Agaricus mushrooms. Food Additives & Contaminants, 19(11), 1028-1033.
Since you have a microbiologically active community, you also have access to the enzymatic pathways. I have not found a specific paper about agaritine during fermentation. I can find other articles describing enzymatic transformations and degradation. Some of these transformations can change the molecule into more toxic forms, and other enzymes move it towards a degraded product. What I expect that you will see is that the net effect of having a complex enzymatic mixture will be faster degradation, even if the pathways may cross the more active toxic intermediates (which would also probably form in your intestine), these will only form for a short time and degrade.
You can refer to the paper below for specific examples of the enzymatic transformations that I am referring to. In this paper, the enzymes come from mushrooms that are ground into a liquid, and so they are mushroom enzymes. In the context of fermentation the source of the enzymes would be excreted by the fermenters into the ferment. These enzymes would likely not be specifically evolved for agaritine but instead represent general classes of enzymes that affect functional groups that are present in agaritine. It is difficult to make specific predictions.
Walton, K., Coombs, M. M., Walker, R., & Ioannides, C. (2001). The metabolism and bioactivation of agaritine and of other mushroom hydrazines by whole mushroom homogenate and by mushroom tyrosinase. Toxicology, 161(3), 165-177.
Thanks for taking the time to do a "quick search". It seems like you did quite a lot of reading. I have a bit of difficulty following some of the reasoning. Can I ask if you used an LLM chatbot to assist you in your answer?
No problem! I searched "Agaritine degradation" in Google Scholar and selected to those two articles from the results page as they seemed relevant. I also searched for more specific fermentation based papers but did not find any - this is what I mean when I say quick search.
I did not use an LLM chat bot to formulate the answer, but I did copy and paste it to ChatGPT and asked whether it agreed. I often do this in case it catches some obvious mistake. But it did not suggest any corrections, and it did not affect my answer. So an LLM chatbot did assist me in validation.
If you want I can explain some of the reasoning in more detail. Figures 1 and 3 of the first paper have data on what happens when agaritine is dissolved in water in the presence of air ('open vial'), no air ('closed vial'), and at a low pH with a closed vial. I think that these two figures are the most relevant to this particular question, as they give you an estimate to how fast agaritine will break down due to conditions that are easy to control and measure. Other types of microbiological activity can have an effect, but in this case it is not essential to invoke these more complicated processes.