Accelerated Stability Tests of Moisture‐sensitive Products in Permeable Packages at High Rates of Moisture Gain and Elevated Temperatures

The isothermal “no model” method of accelerated stability testing, which was developed for isothermal storage of moisture‐sensitive dehydrated products packaged in water‐vapor‐permeable containers, was expanded to include storage at different temperatures. The expanded method can be applied to dehydrated products when moisture content changes continuously during storage and when rate of deterioration is only dependent on moisture content and temperature. Knowledge of how rate of deterioration depends on moisture is not required, but it is assumed that at each moisture level the temperature dependence is given by the Arrhenius equation. The method is based on accelerating the deterioration process by subjecting the product to high rates of moisture uptake at elevated temperatures. The mathematical procedure of predicting the extent of deterioration for any combination of package‐storage conditions is based on a transformation of data to an arbitrarily determined reference moisture gain curve and an extrapolation to other temperatures by the Arrhenius equation. The method successfully predicted the loss of ascorbic acid in stored tomato powder and the extent of browning in dehydrated cabbage.