Ev tipi hibrit (konvaksiyonel-mikrodalga) firinda kimi meyve ve sebzelerin kurutma ve kalite parametrelerinin incelenmesi

Two different drying techniques were tried for drying of apple, apricot, sour cherry, tomato, red pepper and mint samples; convectional (CD) at 50, 60, and 70 °C and hybrid (HD; microwave-convection) drying at 120, 150, and 180 W microwave power coupled with 50, 60, and 70 °C hot air. Both sources of energy were applied simultaneously during the whole hybrid drying process. Drying time decreased and drying rate increased with increasing air temperature and microwave power for CD and HD, respectively. Drying generally occurred in falling rate period. In order to describe drying behavior of food materials nine semi-theoretical models were tested. CD data of apple, tomato, pepper and mint and HD data of apple, apricot, sour cherry and tomato samples were fitted the best by modified Logistic model. However, CD data of apricot and sour cherry were fitted the best by Page and Verma model respectively, and HD data of pepper and mint samples were fitted the best by logarithmic model. Temperature of food materials sharply increased at the beginning of the drying, then reached equilibrium with drying medium and finally increased at the end of the drying process. Effective moisture diffusivity and thermal diffusivity values were calculated by use of Fick's law. Activation energy values of the drying processes were obtained by use of effective moisture diffusivity, thermal diffusivity and the rate constant value of the best model. Energy consumption and specific energy requirement of hybrid drying method was lower and energy efficiency was higher than convectional method. Drying treatment reduced significantly (more than 60%) total phenolics content (TPC), vitamin C content (more than 73%) of all dried food materials and antioxidant capacity (AOC) of apricot, sour cherry and mint samples. The L* value of all food materials decreased after drying treatments except sour cherry. Total color difference, rehydration capacity, hardness and chewiness of dried materials increased with air temperature for CD and microwave power for HD. Rehydration capacity of hybrid dried samples was higher than convectional dried counterparts. Hardness and chewiness increased with increasing air temperature and microwave power for CD and HD, respectively.