Study On Process And Kinetics Of Hot Air Combined Vacuum Microwave Drying For Colocasia Esculenta Schott Crisp Slices

With the rapid development of agricultural products processing,how to make full use of good Colocasia Esculenta Schott,to promote the development of Colocasia Esculenta Schott industry has become one of the common problems of the attention of scholars of China and abroad.The development of non Fried Colocasia Esculenta Schott crisp slice of health food is one of important methods of resource processing and utilization of Colocasia Esculenta Schott.has a great practical significance.Therefore,this paper are study the processing of Colocasia Esculenta Schott slices by hot air and vacuum microwave drying,and to establish the corresponding mathematical model,and analysis the regularity of moisture migration inside Colocasia Esculenta Schott chip by Magnetic Resonance Imaging(MRI)and Nuclear Magnetic Resonance(NMR)techniques.1.The drying characteristics of Colocasia Esculenta Schott were studied by hot air drying,vacuum microwave drying,hot-air drying combine vacuum microwave drying.The drying curves and drying rate curves were determined,and fitting the Colocasia Esculenta Schott slices hot-air and microwave drying kinetics curves by 5 kinds of drying mathematical model(Page model,Henderson model,Logarithmic model,Wang and Singh model,and Midilli model),in order to establish the corresponding dynamics model.The results show that the Midilli model can be used to describe the drying process of Colocasia Esculenta Schott slices,said the Page model can be used to describe the drying process of Colocasia Esculenta Schott slices by using separate vacuum microwave drying process,the later described the process of vacuum microwave drying could be described by Midilli model.2.Studied the regularity of moisture migration inside Colocasia Esculenta Schott chip by Magnetic Resonance Imaging(MRI)and Nuclear Magnetic Resonance(NMR).The proportion of bound water,half bound water and free water in Colocasia Esculenta Schott slices were analyzed by different T2 relaxation time.Though simulation,Colocasia Esculenta Schott slice uneven drying when using a hot-air drying method,After the free water and the half bound water were removed,the remaining bound water will be removed for a long time.The long time of drying resulted in the hardening of Colocasia Esculenta Schott slices,which greatly affected the quality of Colocasia Esculenta Schott slices.On the Hot air combined vacuum microwave drying process of Colocasia Esculenta Schott chips,after hot air drying has remove most of the free water,then turn into the vacuum microwave drying,the combined with half water and bound water can be removal only through 6mins,and in the process of drying,microwave puffing effect to Colocasia Esculenta Schott slices bound water within the semi combined water migration.3.Studying the Processing technology of drying Colocasia Esculenta Schott adopt hot air and microwave vacuum.Firstly,the brittleness,expansion rate and color were used as evaluation indexes,according to the single factor(including hot air velocity,hot air temperature,vacuum degree,microwave power,etc.),select the appropriate factors,with the orthogonal test method of Colocasia Esculenta Schott crisp slice drying combined with vacuum drying parameters,optimum the best conditions.The results showed that the optimum conditions of combined drying with hot air and vacuum microwave were:Microwave power were 500W,conversion point moisture content were 25%,slice thickness were 4mm,and vacuum degree were 0.09Mpa.Under this condition,the dried Colocasia Esculenta Schott chip puffing rate was 116.24%,the puncture force was 2867.261g,and the Colocasia Esculenta Schott slice was in a good of crisp.