This Microsoft Excel demonstration worksheet file estimates the equilibrium water activity, AwStar, of a dry multicomponent food mixture stored in a hermetically sealed container. It is assumed that the ingredients do not interact chemically, that the temperature is constant and that the amount of moisture absorbed by or released to the atmosphere trapped in the container is negligible. The n ingredients' moisture sorption isotherms are described by n equations, each one of which may or may not be the same as the equation of another ingredient. Input moisture values should be entered on a wet basis and will be converted to a dry basis for calculation and plotting.
Model calculation; aw
Provider - Source:
University of Massachusetts at Amherst