I'm planning to do a Lentinula edodes (shiitake) and Trametes versicolor polysaccharides extraction to use as a food supplement.

Polysaccharides are insoluble in cold water but are soluble in hot water. So the idea is to boil the dried shroom powder, filter the extract and than let it cool down to about 4C to let the actives precipitate so they can be filtered out by vacuum filtration.

In the literature about extraction of polysaccarides, usually 50% ethanol is added to the filtrate before precipitation.

Does anyone know what the benefit of this is as the polysaccharides are both insoluble in ethanol as well as cold water, so what's the added value of adding expensive ethanol?

YES SIR!

I have done a lot of this myself with both chaga and reishi mushrooms. Shiitake is great too but it tastes good to me to extract, I eat it whole in soups.

Hot water extraction is used to extract polysaccharides, but for these woody tree mushrooms it can take many hours of boiling. Long hours of boiling can hydrolyze the polysaccharides, so the goal is generally to have the most efficient extraction in the shortest amount of time. Microwave extraction apparently is very effective in lessening the amount of time needed, one study I read did as well in 30 minutes as boiling did in 6 hours.

As for your question,
My guess is that they are using the 50% ethanol to help crash out the sugars, if they are less soluble, as well it can allow you to bring the temperature down to 0C and below without freezing the filtrate.


---

In this paper I attached they do it in it even less time, super heated water extraction, though in this case they also have a special pressure vessel in the microwave for the extraction.

And they also use ethanol precipitation to recover the sugars.

Thanks for your reply and the paper.
I'll try and experiment with a pressurecooker to reduce boiling time on the Tramates. I don't have a microwave anymore. Once it broke down I didn't feel the need to get a new one. It motivates me to cook fresh as much as possible.

I also like the shiitake in dishes but the Tramates I can't get used to. It's to rubbery for my likings. But it's in Tramates where the polysaccharide Kretin has te best oral intake results in boosting your immune system according to several Japanese studies. The polysaccharide Lentinan found in shiitake seems to be less effective when taken orally.