Optimization Of Drying Process Of Radix Rehmanniae

Radix Rehmanniae is the fresh or dry root tube of the Scrophulariaceae plant Rehmannia glutinosa Libosch,which is a traditional Chinese medicine herb and the principal ingredient of many Chinese patent medicines.It has a high medicinal value.The water content of fresh Rehmanniae is large,so it easily to get mildewed in the process of storage and transportation.Mold will lead the medicinal value of herbs to reduce or even completely inedible.Drying can effectively prevent fresh Rehmanniae from mildew.Drying is an important part of the processing of Rehmanniae,drying will directly affect the quality and efficacy of Rehmanniae.Therefore,the correct choice of drying method for ensuring the quality of Radix Rehmanniae is of great significance.In this paper,habitat of different drying methods were compared,the influence of process parameters on the drying characteristics and quality of habitat,and the process parameters were optimized.Dried herbs pretreatment process is an important part,will have an impact on the quality of medicines,the paper before drying habitat also studied.In this paper,Radix Rehmanniae of different drying methods were compared,the influence of process parameters on the drying characteristics and quality of Radix Rehmanniae,and the process parameters were optimized.Dried herbs pretreatment process is an important part,that will have an impact on the quality of medicines,so in this paper pretreatment process before drying of Radix Rehmanniae were also been studied.To study the effect of the quality of Radix Rehmanniae before the drying process,the paper choose five kinds of soaking solution to study the effects of pre-treatment quality of Radix Rehmanniae.The results showed that soaking type had significant impact on the loss rate of Catalpol.And other than acetic acid soaking solution significantly reduces the loss rate of Catalpol.Rehmannia at a slice thickness of 5mm,before the treatment of Catalpol loss rate of the minimum alcohol under the combined action of 0.02% acetic acid solution.In order to get the suitable drying method,the quality of Rehmannia in natural drying,vacuum drying and heat pump drying was studied in this paper.The results obtained from the experiments were that the drying time was in the order of natural drying,the drying time is the longest,the second is vacuum drying,and the last is the heat pump drying.It can be seen that the heat pump drying time was the shortest,that means the energy consumption was low.The heatpump drying of Rehmannia had the lowest loss rate of Catalpol and the highest quality of dry products.Then,this paper researched the drying characteristics of Rehmannia in heat pump drying.The results showed that the higher the temperature,the shorter the wind speed,the shorter the time required,the greater the drying rate.With the decrease of the thickness of the slice,the drying time was reduced and the drying rate increase.Finally,the process parameters of heat pump drying were optimized.The experiments results showed that when the drying temperature was 49.8 ?,the wind speed was2.67 m/s,the slice thickness was 3.5 mm,Catalpol loss rate of the minimum was10.2%.Response surface analysis results showed that,the control range of the parameters for drying temperature was from 45 to 56 ?,wind speed was from 1.6 to3.5 m/s,slice thickness was from 2 to 5.2 mm.In these ranges,Catalpol loss rate can be controlled below 20%.