REHYDRATION OF FREEZE-DRIED STRAWBERRIES AT VARYING TEMPERATURES

Strawberries (var. Seascape), cut in halves or 5‐mm slices, were freeze‐dried at a heating plate temperature of 55C for 28 h. Freeze‐dried products were then rehydrated at 0, 20, 40 and 80C in distilled water. The progression of the rehydration coefficient (RC) was followed as a function of time (up to 25 min). Less than 2 min were necessary to fully rehydrate the slices and less than 5 min for half strawberries. The results showed that halved and sliced freeze‐dried strawberries had higher RCs when rehydrated at a temperature near 0C. A simple diffusive‐type equation was used to represent water uptake during rehydration. Effective diffusion coefficients were modeled as a function of temperature using an Arrhenius‐type relationship.