Hot Air Drying Of Mango Preserved Fruit And Combined-Drying Comparative Study

Processing conditions of preserved mango by hot-air drying,(HAD) far-infrared-vacuum drying (FIVD) and microwave-hot-air drying (MHAD) were optimized by orthogonal test and response surface methodology, with Jinhuang Mango as the raw material. Sensory qualities, VC content, reducing sugar content, reconstitution properties, product textural properties, chromaticity and energy consumption were taken as evaluation indexes. Drying kinetic equations were gotten with fitting method. Each drying process was analyzed and the end products were finally compared with those processed by vacuum-freeze drying (VFD). Main results for this study are as follows:l.The optimal processing condition of HAD:Vc addition0.15%, CaCl2addition0.20%, white sugar addition40%, drying at55℃for5.0h.2.The optimal processing condition of FIVD:vacuum degree of0.0423MPa, heating at55.4℃for4.5h.3.The optimal processing condition of MHAD:hot-air drying at55℃for1.5h, and microwave drying under300w power for3min. 4. Analysis the Drying Model of different drying technology.5.MHAD provided not only the shortest time and energy consumptions, but also higher preserving rates of VC and reducing sugar of preserved mango, ranked only second to that of VFD.6.VFD provided a better color of preserved mango than FIVD, followed by MHAD, with HAD as the worst. Significant differences in hardness were also observed in preserved mango:HAD provided a pretty harder texture than FIVD and MHAD.7. Energy consumption:HAD unit of electricity consumed28.15kwh/kg,FIVD unit of electricity consumed12.61kwh/kg,MHAD unit of electricity consumed only7.63kwh/kg.The study demonstrated that the process with osmotic dehydration as a mango pretreatment,followed by mirowave-hot-air drying,has remarkably shortened the drying time, reduced the energy consumption and improved the sensory quality of end-products.