Study On The Effect Of The Physical And Chemical Properties Of The Water Extract Of Traditional Chinese Medicine On The Spray Drying Process

Objective:By analyzing the data of the physicochemical properties of traditional Chinese medicine?TCM?extracts and the phenomena in spray-drying process?spray process,drying process and powder collecting process?,to clarify the specific components which caused hot-melt sticking in spray drying.Moreover,to established the correlations between the physicochemical properties of TCM extracts and the parameters in spray-drying process,which provided basic theory support for the spray-drying technology in TCM extracts.Methods:In this study,the methods for determining the content of 8 types of chemical components?citric acid,glucose,protein,etc.?were established with 66 kinds of most common used Chinese herbs.Physical properties?equilibrium surface tension,dynamic surface tension,etc.?of Chinese herbal extracts were determined and the powder collection rate and wall stickiness condition of TCM were recorded.The spray process and drying process of TCM were characterized,too.By statistical analysis and data mining,to analyze potential hidden correlation among the physicochemical properties of TCM extracts,spray process,drying process and powder collecting process,in which models of the significantly correlation parameters were studied.Results:?1?The selected herbs were taken from different parts,and those herbs were representative in this study.In addition,the determination methods of physicochemical properties of TCM extracts were established and optimized.The contents of organic acids and low molecular weight saccharide in the extracts of fruits Chinese drugs was higher.The dynamic surface tension was better than the equilibrium surface tension in characterizing the TCM extracts'surface tension variety in kinstate.There was no correlation between chemical components and physical properties of TCM extracts through statistical analysis.?2?The traditional Chinese medicine extract was atomized by a twin-fluid atomizer.As the vertical distance?H?from the nozzle increased,the droplet size distribution were increased,and the spray field distribution changed from narrow to wide.At the same height,the droplet size increased from the center to both sides.And the droplet size decreased with the increase of atomization pressure.Pearson correlation curve analysis showed that there was a significant positive correlation between particle size distribution D50 and dynamic viscosity.The curve was fitted to the D50 and the dynamic viscosity?x?to obtain a model:D50=16.202-3.749x+1.359x²-0.078x³.?3?Characterizing the drying process of TCM extracts by the change of surface viscosity of single drop in drying progress.A negative correlation between the dynamic viscosity and the angle and a positive correction between the rise rate of surface viscosity of single drop and dynamic viscosity were obtained by data mining.The ascending rate,descending rate,angle value,and power collection rate were analyzed by PCA.When two principal components were taken,from the HCA diagram and PCA score diagram,it was found that the tested medicinal materials could be clearly divided into two categories:the powder collection rate>50%and the powder collection rate<50%.?4?7 chemical components of low molecular weight saccharide,organic acid,protein and tannin were taken as independent variables for PCA analysis and HCA cluster diagram.The results showed that the medicinal materials could be significantly distinguished into two types:hot-melt sticking?powder collection rate=0?and non-hot-melt sticking?powder collection rate>0?.Next,L-malic acid,citric acid,fructose and glucose were suggested as the difference factors for the hot-melt sticking of the extracts by OPLS-DA analysis.Through the analysis of entropy-based mutual information and association algorithm,the following results were obtained:the importance of 8 chemical indicators in the effect of the powder collection rate were glucose,fructose,L-malic acid,citric acid,sucrose,tannin,polyphenols and protein;the importance of 5 physical indicators in the effect of the powder collection rate were DST_10ms,dynamic viscosity,DST_94ms,DST_1000ms and equilibrium surface tension.Conclusions:Based on the detection of 66 kinds of traditional Chinese medicine extract analysis,it was preliminarily deemed that the chemical compositions of TCM extracts had no direct influence on the atomization process and drying process of the twin-fluid atomizer,but there was a significant correlation with the hot-melt stickiness effect.It was thought that the small molecular components?L-malic acid,citric acid,fructose,and glucose?were the key factors that lead to the hot-melt sticking of TCM.In the process of atomization by twin-fluid atomizer,the dynamic viscosity of the TCM extracts had the greatest influence on the droplet size,and the droplet size distribution D50 could be deduced from the dynamic viscosity.In the drying process,with the increase of the dynamic viscosity of the TCM extracts,the rise rate of the surface viscosity of the single drop was accelerated,and the angle value that represents the rise and fall trend of the surface viscosity of the single drop might decrease.Ultimately,the drying rate of the TCM extracts was accelerated in a certain range of dynamic viscosity.The angle value could be used as an index to judge whether the TCM extracts were suitable for spray drying or not,and to evaluate the degree of wall stickiness of the TCM extracts in spray drying.The dynamic viscosity and DST_10ms of TCM extracts were the important factors affecting spray drying effect.In the experiment,it was found that after alcohol precipitation,some TCM extracts appeared hot-melt stickiness.Aiming at this phenomenon,it needed further testing and research.