With respect to materials, cap powders had higher values
in polysaccharide solubility but lower values in protein solubility
than stipe powders with the same size-reduction method. The fact
might relate to protein content in the powders. Assuming the protein
solubility, at a fixed sample/extractant ratio, was mainly depended
on the protein content in the powder as observed in
various industrial extractions. The higher the protein content in
the test powder, the higher the protein concentration in extract
was. The protein contents of cap powders (16.71–18.29 g/100 g)
were much higher than that of stipe powders (5.61–7.20 g/100 g). This brought about the fact that the protein solubilization
of the powders with higher protein content reached to equilibrium
with much more protein remaining in the powder than those with
lower protein content.