Investigating the effects of convective drying conditions on some qualitative and bioactive characteristics of cantaloupe slices using the response surface method

Drying is a common technology that provides a long post-harvest storage period for products such as cantaloupe. Hot air drying is a method that, if the conditions are optimized, gives the product better appearance and improved textural properties. In this study, drying time, specific energy consumption, energy efficiency, shrinkage, rehydration ratio, changes in total color, phenol and antioxidant content were modeled to optimize drying factors (air temperature and air velocity) using the response surface method. The drying processes of the samples were investigated at three temperature levels of 50, 60 and 70 °C and three velocity levels 0.5, 1 and 1.5 m/s. For optimization of the drying conditions (drying time, SEC, energy efficiency, shrinkage, RR, color changes, TPC and AC), the influences of two levels of independent variables including air temperature and air velocity were assessed by response surface method through a face-centered central composite design. The results showed that in the drying of cantaloupe using the hot air method by increasing the inlet air temperature and decreasing the air velocity, energy efficiency, rehydration ratio, total phenol content and antioxidant were increased, while drying time, specific energy consumption, shrinkage and color changes were reduced. The optimum point for drying cantaloupe samples was obtained at an air temperature of 70 °C and air velocity of 0.5 m/s. The results showed that drying at higher temperatures increases the desirability index of the model obtained from the response surface method. The authors believe the outcomes of the present study can be used as a framework for choosing efficient drying parameters for drying cantaloupe or similar fruits in HAD systems