Research On Solar Drying Charactreristics Of Ziziphus Jujuba

In order to reduce the possibility of poor sanitation,rotting and low output in the open air condition,solar wall collector drying,PVC greenhouse drying,glass greenhouse drying,PC greenhouse drying and open air drying characteristics of Ziziphus jujube had been studied in this paper.The research results can provide guidance for practical Ziziphus jujube solar drying.Ziziphus jujube were dried in solar wall collector and open air condition.In order to get dry basis moisture and drying rate,air temperature,air relative humidity and surface temperature of Ziziphus jujube in different lays were determined,combined with sensory evaluation to analysis the quality of dried Zizipus jujube.The results showed that the drying time of solar wall collector was nearly 60% percents of the drying time of open air.It token only 9 days to reach the safe water content.At the same time,it had higher sensory score and vitamin C content after solar wall collector drying.The fastest frying rate was the 4th floor of solar wall drying chamber,and the slowest moisture content decreased was the 2th floor of solar wall drying chamber.Ziziphus jujube were dried in greenhouse drying devices and open air condition.In order to get the characteristics of Ziziphus jujube,air temperature,air relative humidity and surface temperature of Ziziphus jujube in different lays were recorded,combined with sensory evaluation to analysis the quality of dried Zizipus jujube.The results showed that the light transmission property of glass greenhouse was the best,and the temperature in it could reach 40 ?.Good insulating effect,drying speed and high relative humidity were showed in glass greenhouse.It token only 7 days to reach the safe water content.At the same time,it had higher sensory score and lower vitamin C content after glass greenhouse solar drying.Surface temperature of Ziziphus jujube and drying rate were reduced with layer down of the three greenhouse solar drying devices.Solar wall collector and three solar greenhouse drying devices were compared with Ziziphus jujube drying characteristics.The results showed that the heat collecting capacity of the solar wall collector was good,and air relative humidity was low.The highest temperature of the drying chamber was the glass greenhouse solar drying device.Ziziphus jujube sensory evaluation score was high in solar collector drying device after drying,with high vitamin C content.Total sugar content was closer in solar drying device and glass greenhouse device.Based on the above results,the solar wall collector drying device was the most suitable solar drying device of Ziziphus jujube...