Kinetics of moisture uptake of osmo-foam-mat dried mango powders and application of sorption isotherms to shelf-life prediction.

摘要

Kinetics of moisture uptake by foam-mat dried powder from mango pulp were evaluated at 4 temp. (10, 20, 30 and 40 degrees C) and 2 RH (55 and 80%), while moisture sorption data for shelf life prediction was obtained at the same temp. and at 8 aw ranging from 0.032 to 0.925. Rates of moisture uptake were high in the first 2-4 h at any given storage temp. and RH. Moisture uptake generally decreased with increase in storage temp. but did not show a defined trend after the first few h. The rate of moisture uptake was higher at 55 than at 80% RH. Effective diffusivities of samples incorporated with foam stabilizers were higher due to high porosity. Moisture uptake obeyed the penetration theory, indicating that the process followed Fick's law. Predicted shelf-life of the powders generally decreased with increased storage RH and temp. The predicted shelf-life of the powders was generally >365 days. The shelf life of powders incorporated with foam stabilizers was generally shorter as they had lower equilibrium moisture content. Predicted shelf life of the powders was longer in packaging materials with low permeability to thickness ratio.