Control of crust permeability and crispness retention in crispy breads

Crispness of bread crust is rapidly lost after baking. It is known that the speed of this loss is influenced by the water vapor permeability of the crust. A high water vapor permeability benefits crispness retention but could lead to crumb dryness. In this paper we aimed to determine the water vapor permeability that is optimal for both crispness retention and crumb softness retention. The water vapor permeability of crust was changed by creating different quantities and sizes of channels in the crust. The instrumental and sensory evaluation of the breads stored at 40% relative humidity showed that the water vapor permeability for optimal crispness and crumb softness retention was 8×10-9 g/(m s Pa). Based on this knowledge we suggest possible combinations of the quantities and sizes of channels to create breads with an up to eight-fold longer sensory crispness retention without decreasing crumb softness retention. In addition, our data allowed us to develop a model describing the water vapor permeability of crust with channels.