Experimental Study On Camellia Oleifera Seeds Dried By Hot Air

Camellia oleifera is one of the four major woody oil species in the world. According to the statistics, the planting area was3.5million hectares and the annual output of camellia oleifera seeds was1.73million tons in2012. But the related research on drying of the seeds was still in preliminary stage and has been less reported. In this paper, drying technology was studied with fresh wet camellia oleifera seeds as test materials. The purpose of this research was to provide experiment data and technology support to develop drying technology and equipment.On the basis of drying characteristics research, dry camellia oleifera seeds under different drying parameters (hot air temperature, hot air speed, material thickness) and draw drying curve. the sensory quality were evaluated and acid value and peroxide value were determined with relevant analysis.The effect of hot air drying parameters (hot air temperature, hot air speed, material thickness) on the process parameters (drying and energy consumption) of drying process was studied during the drying experiment by orthogonal experiment method(L9(34)) with camellia oleifera seeds. A comprehensive evaluation of the camellia oleifera seeds by using factor analysis. The drying parameters of camellia oleifera seeds were optimized and validated.Conclusion:(1)The research on drying characteristic of camellia oleifera seeds shows that drying speed changes from high to low in the drying process. The main factors affecting the drying rate includ the resistance of the shell and transfer rate of the internal moisture.(2) The study of drying parameters showed that when the temperature and air speed of hot air become higher, the drying time to balance water becomes shorter within a certain range. When the material thickness becomes higher, the drying time becomes longer to balance water. The sensory properties changes significantly compared to the natural drying when the hot air temperature is95℃and105℃.(3) The optimization test showed that the optimum process parameters:air speed of14m/s, air temperature of85℃, the material thickness of40cm when the drying time as the evaluation index. The optimum process parameters:air speed of14m/s, air temperature of65℃, material thickness of50cm when the drying energy consumption as the evaluation index.The electron microscope scanning test results show that the drying temperature is higher, the micro surface structure of the camellia oleifera kernel is more uneven and have the greater gap.(4) The results of tempering drying process show that the influence of tempering process on the precipitation rate is not big at the beginning of the drying process. When approaching the balance wate, rate of precipitation in the tempering drying process is equal in hot air drying stage. So the energy consumption can be effectively reduced when the tempering period was added.Air speed and temperature has a significant impact of the drying time and energy. Temperature has a significant impact of on the microcosmic surface structure. Add the tempering drying process can raise the utilization ratio of heat energy.