Key takeaways
- Polysaccharides are large carbohydrates made of many sugar units.
- Mushrooms contain beta-glucans, chitin, heteropolysaccharides and protein-bound polysaccharides.
- Mushrooms contain little starch, but grain does.
- A “polysaccharides” figure is broad and can include starch.
“Polysaccharides” appears on many mushroom labels and in much research. It is a broad term, and understanding what it covers helps you read both labels and studies more accurately.
What is a polysaccharide?
A polysaccharide is a long chain of sugar units. Starch, cellulose and chitin are all polysaccharides. They differ in which sugars they contain and how those sugars are linked.
Polysaccharides in mushrooms
- Beta-glucans: glucose chains in the cell wall. See Beta-Glucans in Mushrooms Explained.
- Chitin: a structural polysaccharide containing nitrogen. See Chitin and the Fungal Cell Wall.
- Heteropolysaccharides: chains containing several different sugars.
- Protein-bound polysaccharides: polysaccharides attached to protein.
- Storage carbohydrates: small amounts of glycogen and related compounds.
Polysaccharides versus starch
Mushrooms themselves contain little starch. Grain does. When a product made from mycelium on grain is tested for “total polysaccharides”, grain starch can make up much of the result. See Alpha-Glucans, Starch and What They Can Tell You.
Extraction
Most mushroom polysaccharides are water-soluble when heated, which is why hot water extraction is the traditional method. Alcohol causes many of them to precipitate. See Hot-Water Mushroom Extraction Explained.
What this means on a label
A “polysaccharides” percentage is a broad measure. It doesn’t tell you how much is beta-glucan, or whether starch is included. Look for a specific beta-glucan figure, measured by an appropriate method, if you want detail. See Beta-Glucan Testing Explained.