Commercial mushroom processors currently lose approximately 30 percent of the mushroom weight due to shrinkage during processing (blanching and canning) , resulting in substantial economic losses . Microscopy was used to assess the extent and type of chemical and structural changes induced by processing mushrooms and causing shrinkage. Scanning electron microscopy revealed that the processing operations including vacuum hydration , blanching , and thermal treatment do not damage the integrity of the tissue. Light microscopy revealed that the morphology of the tissue, shape and spacing of cells, appear similar for raw and processed mushroom tissue . However, the intra ce ll ular material remained indistinct for both tissue types, and the processed tissue appeared distorted. Transmission electron microscopy revealed that commercial mushroom processing caused intracellular damage to the tissue. The heat treatment caused the coagulation of cytoplasmic material and the disruption of intracellular membranes, resulting in the loss of water holding capacity of the tissue. Therefore, shrinkage of processed mushrooms results from "denaturation" of the organelles and the associated loss of water holding capacity by those organelles.
Jasinki, E. M.; Stemberger, B.; Walsh, R.; and Kilara, A.
"Ultrastructural Studies of Raw and Processed Tissue of the Major Cultivated Mushroom, Agaricus bisporus,"
Food Structure: Vol. 3
, Article 12.
Available at: http://digitalcommons.usu.edu/foodmicrostructure/vol3/iss2/12