ObjectiveTo explore the effects of different drying conditions on the appearance traits and intrinsic quality indicators of Pinelliae Rhizoma， and to screen suitable drying conditions for its standardized production and quality evaluation.MethodsThe drying conditions for fresh Pinelliae Rhizoma were processed using three methods： lime-assisted sweating， intermittent drying， and sun drying. Visual analysis was employed to measure the surface， cross-section， and powder color of the samples. A texture analyzer was used to determine the hardness of samples under different drying conditions. The total starch content was calculated by measuring the contents of amylose and amylopectin in the samples. High-performance liquid chromatography（HPLC） was used to determine the contents of seven nucleoside components （uracil， hypoxanthine， uridine， inosine， guanosine， β-thymidine， and adenosine） in the samples. Pearson correlation analysis was conducted to explore the correlation between the external characteristics and intrinsic indicators of the samples. Cluster analysis was performed to investigate the factors affecting the drying conditions of Pinelliae Rhizoma. Principal component analysis（PCA） was used to rank the data of various indicators comprehensively， and partial least squares discriminant analysis（PLS-DA） selected differentiating components based on variable importance projection（VIP） values greater than 1. Furthermore， Investigate whether there is a difference between the optimal drying conditions for Pinelliae Rhizoma and the traditional sun-drying method using an independent samples t-test.ResultsIn the context of intermittently dried Pinellia Rhizoma samples， it has been observed that as the temperature rises， the color of the samples progressively darkens while their hardness diminishes. Concurrently， the contents of extractives， total starch， uridine， and adenosine exhibit an upward trend， whereas the contents of uracil， hypoxanthine， and inosine display a downward trajectory. In contrast， Pinellia samples subjected to lime-mixed sweating demonstrate a higher overall content of extractives compared to those that have been intermittently dried. As the quantity of lime increases， the hardness and the aggregate content of nucleoside components in these samples generally decrease， while the total starch content experiences an increase.The results of the correlation analysis indicate that the L* comprehensive score is significantly and negatively correlated with the contents of uracil， hypoxanthine， and inosine， while it is significantly and positively correlated with the contents of uridine， guanosine， and adenosine. Hardness is found to be significantly and negatively correlated with adenosine content， yet significantly and positively correlated with the contents of inosine， uracil， and hypoxanthine.Upon comprehensive consideration and evaluation through principal component comprehensive scoring， the method of 5% lime-mixed sweating for 6 days emerges as the top-ranking approach. The independent samples t-test results reveal that， with the exception of extractive content， there are no statistically significant differences between the 5% lime-mixed sweating for 6 days and the traditional sun-drying method in terms of other content determination indicators.ConclusionThe whiteness and firmness of Pinelliae Rhizoma exhibit significant positive and negative correlations with its chemical composition. Uridine， uracil， guanosine， adenosine， and inosine have been identified as the key constituents responsible for the quality variations of Pinelliae Rhizoma under different drying conditions. The lime-mixing and sweating drying method， which has been optimized in this study， can be proposed as a viable alternative to the traditional sun-drying method. This method not only ensures the quality of the medicinal material but also effectively reduces the drying time of Pinelliae Rhizoma and prevents mold contamination. It thereby provides a valuable reference for the standardization of drying conditions and the establishment of quality evaluation criteria for Pinelliae Rhizoma.

Pinelliae Rhizoma;standardization;lime mixed with sweating;intermittent drying;appearance;intrinsic indicator;high performance liquid chromatography（HPLC）