Changes in the physical properties of bananas on applying HTST pulse during air-drying

The effect of high temperature (HTST) pulse on the air-drying of banana slices was studied and compared with the conventional air-drying process. The Exponential and Page models fitted the experimental data of the dehydration kinetics for both processes well. The different drying treatments led to distinctive structural changes in the samples, affecting the shrinkage and porosity. The combined HTST/air-drying process simultaneously puffed and dried the banana slices, resulting in reduced shrinkage compared with the conventional air-dried samples. For conventionally air-dried samples, the increase in porosity reached a value of 32% at the end of the process. During the HTST/air-drying process, the porosity increment reached values of from 45% to 53% at the end of drying, resulting in the formation of a highly porous structure, which occurred together with an expansion in volume. Structural observations of the banana samples during the processes studied were able to explain the volume and porosity changes. (c) 2007 Elsevier Ltd. All rights reserved.