Banana is one of the most popular fruits all over the world, while, it’s high moisture content prevents long preservation period. Since banana is an un-freezable fruit, thermal processing such as drying could be more appropriate for prolonging it’s shelf life. High energy consumption and being cost intensive are two most important disadvantages of hot air drying. Osmotic dehydration can reduce the drying time by reduction of initial moisture content; however, it’s efficiency is limited. Osmotic assistant dehydration with a non-thermal energy sources like ultrasound waves can improve it’s efficiency. In this research three methods were used for assisting osmotic dehydration in five sucrose concentrations (40, 45, 50, 55 and 60 ° Bx). They were mechanical agitation, indirect sonication and direct sonication. Optimized condition for maximum water loss, minimum solid gain, total color difference and surface area changes was selected by using response surface methodology. The optimum processing condition was direct sonication for sucrose concentration of 53.95%. The accuracy parameters for the optimized condition including mean square error (MSE), normalized mean square error (NMSE) and mean absolute error (MAE) were obtained to be 0.7715, 0.000821 and 0.7802, respectively. Then, the optimized pretreatments were dried at temperatures of 60, 70 and 80 ° C for 7 h. The quality of dried samples was compared with blank dried sample. The result indicated that direct sonication could improve the dehydration of the samples during drying process more efficiently and prevent thermal damages. Morphological features of the treated samples were investigated using electron scanning micrographs. Textural damage and creation of micro channels were observed for the sonicated samples which are responsible for increase in mass transfer coefficients during osmotic dehydration and drying. Appropriate control of operation can be obtained by modelling which can be categorized into empirical and analytical methods. In this research five empirical models were fitted to the experimental data and the result showed that diffusion approach, page and modified page were more appropriate for describing drying kinetics. For mathematical modelling a 1D dimensional cellular automata was used. The model was programmed by MALAB and run for 70000 iterations. The validation of models was performed by calculation of determination coefficient and standard deviation ratio. The result showed good accordance between experimental and predicted data. Keywords : Banana, Cellular automata, Drying, Modelling, Osmotic dehydration, Pretreatment, Ultrasound waves.
