3.2.4. Water activity (aw)
The measurement of water activity has been useful for pre- dicting the stability and safety of foods, with respect to microbial growth, deterioration reactions, and chemical and physical properties (Fontana, 1998). Table 5 presents the water activity of the cake formulations without significant differences over the shelf- life, within the same formulation. A decrease in water activity (aw) of the crumb during storage was expected due to the water migration from the crumb to the crust, but this did not occur.