Interrelationships Between Storage Stability and Moisture Sorption Properties of Dehydrated Foods (Phase II)

摘要

Investigations were made on the moisture sorption behavior and the chemical stability upon storage of freeze-dried beef, sweet potatoes and spinach. Moisture sorption isotherms were determined at 22.0 and 37.8 C using a constant temperature spring balance. On the basis of these isotherms the B.E.T. monomolecular layer of water, heat of adsorption and constants of the Fugassi-Mitchell equation were determined. The foods were stored at three moisture levels, representing values below, at and above the B.E.T. monolayer, under air and under nitrogen, at 25 and 37.8 C for 3, 7 and 11 weeks. To foods were evaluated by a total of ten chemical tests and by limited sensory evaluation. Results showed that deterioration was more pronounced for foods stored under air than under nitrogen. In addition, foods stored at high moisture contents showed more deterioration than foods stored at lower moisture levels. All foods were more stable at the monolayer moisture level. (Author)