Correlation between chemical compositions of traditional Chinese medicine extracts and phenomenon of wall stickiness in spray drying

Abstract

To explore the correlation between chemical compositions (organic acids, small molecule sugars, protein and others) of traditional Chinese medicine extracts and the wall stickiness in spray drying. In this study, 55 types of most common used Chinese herbs were selected to determine the content of 7 chemical components such as citric acid and fructose from plant extraction. The status of wall stickiness was observed during the drying process. The principle component analysis (PCA-X), hierarchical clustering analysis(HCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were then used to evaluate the correlation between each chemical compositions and wall stickiness, so as to look for the essential chemical compositions associated with the wall stickiness. All of the above 3 statistical analysis methods showed significant results in distinguishing the two groups (sticky or non-sticky). PCA-X score chart and HCA clustering scatter plot suggested that the small molecular substance was the main factor causing wall stickiness, which was then proved by the reality where some of the traditional herb extracts were in non-sticky state after drying but in sticky state after alcohol precipitation. OPLS-DA results revealed that L-malic acid, citric acid, fructose and glucose were the difference factors for the wall stickiness of the extracts. Under small molecular components, L-malic acid, citric acid, fructose and glucose were the crucial factors that directly led to the hot melt sticky wall of the herbal extracts, and macromolecular substances might ameliorate the function of wall stickiness.