Study On The Mathematical Model Of Superheated Steam Puffing Fruit And Vegetables And The Application To Puffing Papaya

In this paper, the superheated steam puffing effect of papaya was investigated. A mathematical model of superheated steam puffing fruits and vegetables was established to indicate heat-transfer relationship and puffing dynamics. Based on the above results, the technology parameters were optimized for superheated steam puffing papaya. Hopefully, these will offer ideological guide for study superheated steam puffing fruits and vegetables deeply and systemically in the future, and offer theoretical and technical support for superheated steam puffing papaya. Obtained main results as follows:1. Pre-dried papaya slice was puffed by superheated steam. The samples, pre-dried papaya and puffed papaya, were scanned by using scanning electron microscope to compare the organization structure difference between the two samples. Results showed that puffed papaya after pre-dried had opening porous structure.2. On the basis of the theory of heat transfer, the heat transfer relationship of superheated steam to material before puffing was studied. A general equation of material central temperature and condensation water variance during superheated steam heating process was established, which will offer theoretical guide for the factor control before superheated steam puffing.The mathematic relationship model between the material temperature and superheated steam heating time is as follow:The mathematic model of condensation water content between the material initial water content and superheated steam heating time is as follow:Papaya as an experimental material, experimental verification showed that the above models were able to express the variance of material temperature and condensation water content during superheated steam heating material process before puffing.3. By the analyzing to the dynamic of superheated steam puffing, two puffing drive forces, superheated steam and superheated liquid amount stored in the material before puffing were defined. So the theories of heat and mass transfer, engineering thermodynamics, solid mechanics were used, and a general dynamic equation of superheated steam puffing fruits and vegetables was established that will offer theoretical guide for the dynamic study and control.The dynamic mathematic model of superheated steam puffing fruits and vegetables is as follow:Papaya as an experimental material, experimental verification showed that dynamic mathematic model of superheated steam puffing fruits and vegetables, was able to express the relationship between puffing degree and puffing driving forces.4. The technology of superheated steam puffing papaya was studied systematically. Based on single experiments, the moisture content of pre-dried papaya, the temperature of superheated steam, and heating time were determined as investigation factors. The puffing degree and color difference were chosen as evaluation indexes. The obtained results optimized by a orthogonal test was:22% of the material moisture content,115℃ of superheated steam,40s of heating time. On the conditions, the puffing degree of the papaya was 180%, the influence factors had no significant effect to the color difference of puffed papaya that maintained desirable color.