Research On Drying Characteristics And Quality Of Lily

In combination with blanching pretreatment,hot-air drying and vacuum far-infrared radiation drying,fresh lily was taken as material to research the effect of blanching temperature,blanching time on hot-air drying character and quality of lily.Additionally,kinetics and change of its quality of vacuum far-infrared radiation drying were studied,whose degradation kinetics of lily's stigmasterol was compared with which in the hot-air drying process.What follows were specific contents in this research.(1)To verify the effect of pretreatment on character of hot-air drying and quality of lily,fresh lily was regarded as raw material to research the effect on indexes,which includess available moisture diffusivity,activation energy,total phenol,total flavonoids,color and microstructure,of drying temperature,blanching time,blanching and temperature for dry products of lily.The result shows that: increase of drying temperature,blanching time,blanching temperature can promote the drying rate,shorten the drying duration;available moisture diffusivity of lily during hot-air drying ranging from 0.51×10-10 m2/s to 4.57×10-10 m2/s was calculated,and according to Arrhenius formula,activation energy of hot-air drying was figured out equal to 86.91 kJ/mol without treatment,while equal to 41.38 kJ/mol with the blanching temperature at 100 ?and the length of blanching time being 45 s;content of total phenol,total flavonoids decreases while the blanching temperature gets higher and the blanching time lasts longer;condition that blanching duration being 45 s and blanching temperature being 100 improves the color of dry products;compared with products ?without treatments,lily being blanched for 45 s at 100 ?shrinks seriously.In conclusion,the optimum blanching condition for lily is 100 ?,45 s.(2)To research lily's characters during vacuum far-infrared radiation drying process,with lily at different infrared radiation heater's temperature,different pressure of drying chamber and different thickness of materials being taken as subjects,effects of three influence factors above on character and quality of vacuum far-infrared radiation drying were studied.The results shows that Weibull distribution function can simulate the vacuum far-infrared drying process well(R2 = 0.9953 ~ 0.9997);the size parameter ? of the model is significantly correlated with the infrared radiation heater's temperature(P<0.01).the scale parameter ? of the model is related to the pressure of the drying chamber and the materials' thickness,while temperature does not have significant influence on it;the diffusion coefficient of moisture during drying process ranges between 0.4013×10-9~1.3075×10-9 m2/s and the activation energy of lily during vacuum far-infrared drying process was calculated,55.1303 kJ/mol.Reducing the pressure of the drying chamber does good to keeping the content of the total phenol;both the infrared lily can keep good color in radiation heater's temperature of 140 ?and the pressure of the drying chamber of 12 kPa.(3)In order to study the degradation laws of lily stigmasterol in the process of hot air drying and vacuum far infrared drying,the degradation kinetics of stigmasterol in lily was studied by using fresh lily and its active ingredient stigmasterol.in order to provide basis for controlling the loss of stapleol in drying process of lily.The results showed that the degradation of lily's stigmasterol in the process of hot-air and vacuum far-i nfrared drying was consistent with the first-order degradation kinetics.