As a physician I can testify that human gastric juices contain chitinase, so chitin can be at least, partially digested.
With that in mind, I would assume that drying the whole mushroom than pulverizing in a simple grinder can make a product that is, at least partially, bioavailable.
I separated the following article for you:
Human gastric juice contains chitinase that can degrade chitin
Maurizio G Paoletti et al. Ann Nutr Metab. 2007.
Keep up the good work!
To facilitate I added the abstract:
Chitin digestion by humans has generally been questioned or denied. Only recently chitinases have been found in several human tissues and their role has been associated with defense against parasite infections and to some allergic conditions. In this pilot study we tested the gastric juices of 25 Italian subjects on the artificial substrates 4-methylumbelliferyl-beta-D-N,N’,diacetylchitobiose or/and fluorescein isothiocyanate (FITC) chitin to demonstrate the presence of a chitinase activity. Since this chitinase activity was demonstrated at acidic pH, it is currently referred to acidic mammalian chitinase (AMCase). AMCase activity was present in gastric juices of twenty of 25 Italian patients in a range of activity from 0.21 to 36.27 nmol/ml/h and from 8,881 to 1,254,782 fluorescence emission (CPS), according to the used methods. In the remaining five of 25 gastric juices, AMCase activity was almost absent in both assay methods. An allosamidine inhibition test and the measurement at different pH values confirmed that this activity was characteristic of AMCase. The absence of activity in 20% of the gastric juices may be a consequence of virtual absence of chitinous food in the Western diet.
Copyright 2007 S. Karger AG, Basel.
Just a comment:
The 20% that did not have chitinase activity maybe had neutral stomach pH by using proton pump inhibitors like aciphex, protonix, Prilosec etc Since that activity appears to be dependent on low stomach pH ( high acidity)