مطالعه خشك‌كردن برگ‌هاي نعناع با سه روش متفاوت (همرفت اجباري، بستر شناور و الكتروهيدروديناميك)

چكيده انگليسي :

Study of Three Different Drying Methods of Mint Leaves Forced Convection Fluidized Bed and Electrohydrodynamic Drying Shahabeddine Alinejadi s alinejadi@ag iut ac ir 1 16 2017 Department of Food Sience and Technology Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Naser Hamdami hamdami@cc iut ac ir Dr Morteza Sadeghi sadeghimor@cc iut ac ir Abstract A significant portion of the crops are dry In order to increase shelf life reduce packaging costs reduce transportation costs maintain appearance flavor and production of ready products Electrohydrodynamic EHD method is one of the modern methods In this way the high voltage electric field is used to drying Drying with electro hydro dynamic method is appropriate for sensitive materials such as agricultural products damaged by common drying method by using hot air EHD drying mechanism is generally attributed to electric wind generated by electric field as the fundamental driving force to mass transfer occurs Electric wind to deal more material stems causing displacement and increased surface moisture gradient mass moisture In developed countries mint is among the most important herbs in everyday life are numerous applications In developed countries mint is including the Pharmaceutical plants has numerous applications in everyday life In this study drying mint with forced convection cabinet fluidized bed and EHD methods was studied The still air was used in EHD drying and the temperature was controlled using the oven In the cabinet and the fluidized bed drying Temperature and air velocity control were performed using a control system In EHD drying mint drying experiments were performed at two temperatures 60 and 70 C and three different electrical field strength of 300 350 and 380 kilovolts per meter In cabinet and fluidized bed drying were performed in 60 70 and 80 C Qualitative parameters of dried mint leaves contains rehydration shrinkage water activity color L a b and E and antioxidant activity was measured For data analysis the split plot design was used in a completely randomized design and the effect of each treatment and sampling absolute humidity factors on each of the quality parameters of dried product was checked out The results showed that the effective moisture diffusivity of mint leaves increased with an increase in temperature and electric field strength in EHD drying and increased with increasing temperature in cabinet and fluidized bed dryer and the values obtained were in a range of values obtained for food Using the analytical solution of Fick s second law relationship Crank for infinite solving method the average effective moisture diffusion coefficient estimated 1 37 10 11 2 58 10 11 and 5 44 10 11 square meters per second respectively for cabinet fluidized bed and EHD drying Specific energy consumption that had demonstrated high performance drying system was determined and specific energy consumption of drying mint leaves style cabinet fluidized bed and EHD drying estimated 146 75 475 59 and 506 41 MJ kg of water evaporated Drying method had a significant effect on rehydration shrinkage water activity and color index of dried samples Although mint leaves drying time using EHD method compared to cabinet and the fluidized bed drying was more However due to low energy consumption low shrinkage and more rehydration of dried samples EHD could be a suitable replacement Keywords Drying mint Electro hydro dynamic method Fluidized bed dryer Specific energy consumption

علي نژادي، شهاب الدين

مطالعه خشك‌كردن برگ‌هاي نعناع با سه روش متفاوت (همرفت اجباري، بستر شناور و الكتروهيدروديناميك)

خشك‌كردن نعناع , روش الكتروهيدروديناميك , خشك‌كن بستر شناور , مصرف ويژه انرژي