An important technological and commercial issue in mushroom processing is the loss of mass resulting from pretreatment, especially blanching. According toCzapski (1994), these losses may be reduced by half through the application of
vacuum soaking prior to blanching. Vacuum soaking increased the mass of A. bisporusmushrooms by 55e60%
compared with the raw material; the greatest increase occurred after soaking in the sodium metabisulphite solution
(60%) and the smallest after soaking in the organic acids solution (55%).