Water activity of freeze dried mushrooms and berries.

摘要

Sorption isotherms at 4, 13, and 27oC were obtained for 2 types of berries (strawberries and blueberries) and 3 types of commercial and wild mushrooms (Shiitake Lentinus edodes, Enoki Flammulina velutipes and Morel Morchella esculenta). The productshad been freeze-dried for 72 h and equilibrated over saturated salt solutions in a range of relative humidity from 11 to 87%. The equilibrium moisture content was obtained when there was no appreciable change in sample weight. The sorption of powdered and whole pieces of mushrooms was studied to evaluate possible effects of particle size on sorption characteristics. Two equilibrium models, GAB and one previously developed by one of the authors, were tested against the experimental data to determine themost appropriate mathematical representation. The constants required for each model were determined by non-linear regression analysis.