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Background: Traditional Chinese medicines are usually processed before they are used for clinical treatment. This is done in a way associated with the Maillard reaction. Methods: Based on the Maillard reaction, this paper analyzed the degree of processing of rehmannia root (Rehmanniae radix) relative to the dynamic variation rules of Maillard reaction index parameters, including pH, A420, amino acids, and 5-hydroxymethylfurfural. Furthermore, this study introduced thermal analysis techniques and pyrolysis kinetics to assess the influence of the correlation between processing raw rehmannia root and the Maillard reaction during carbonization. It then went through the whole process of transforming the raw material to end-product in order to explain the scientific connotation of processing it. Results: The results showed that each time rehmannia root was processed, its pH value and amino acid content decreased, while the A420 value and 5-HMF increased. Processing with wine shows a significant difference in these experimental indexes. The position and intensity of the maximum thermal weight loss rate peak of processed rehmannia root at different degrees of processing are different. Comprehensive quantitative 221 ± 0.2 °C for processed rehmannia root carbonization was the processing temperature limit. Moreover, the kinetic solution verified that the activation energy corresponding to the carbonization temperature was close to the maximum value of the activation energy of the whole carbonization process, and the optimal mechanism function was g(α) = ((1 − α) − 1/3 − 1)2. Conclusion: The Maillard reaction occurred during the processing of rehmannia root mixed with carbonization. With each increase of the number of steaming and drying cycles involved in the processing, the level of Maillard reaction increased significantly. The wine-steaming method had a significant effect on the quality of the processed product.

Metabolite profiling in combination with multivariate statistics is a sophisticated method for quality assessment of natural products. For the development of a quality control strategy in Traditional Chinese Medicine (TCM), we have measured the metabolite fingerprints of Rehmannia glutinosa by GC-MS. Plants were grown under different climate and soil conditions in a phytotron and were processed by a variable number of repetitive steps to investigate the effects on both growth conditions and processing for material medica of R. glutinosa. The GC-MS data have been analyzed by principal component analysis (PCA) and the new approach of the ANOVA-simultaneous component analysis (ASCA) which can combine the information from a structured data design with multivariate analysis. The results clearly show the effect of the different factors and indicate directions for process improvement. When plants were grown under various temperatures, humidity and light intensities for a short period (3 weeks), no significant changes on studied metabolites were observed. However, significant changes were found between different processing cycles. The present data clearly indicate the importance of strictly controlling processing in R. glutinosa and illustrate the impact of growth conditions. This is the first report on the metabolite profile of R. glutinosa that provides a base for the establishment of a quality control strategy. © Georg Thieme Verlag KG Stuttgart.