1.Investigation of Effect of Different Drying Conditions on Appearance Characteristics and Internal Indicators of Pinelliae Rhizoma Based on Standardization
Suqing LIU ; Xueli ZHANG ; Jing ZHANG ; Cong YANG ; Changfu YANG ; Jun YU ; Bingpeng ZHENG ; Huiwu LI ; Yanhua JIANG ; Chang LIN
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(16):208-215
ObjectiveTo explore the effect of different drying conditions on the appearance and intrinsic quality indicators of Pinelliae Rhizoma for screening suitable drying conditions, so as to provide reference for its standardized production and quality evaluation. MethodsDifferent dried samples of Pinelliae Rhizoma were prepared by lime-assisted sweating method and intermittent drying method. Visual analysis was employed to measure the color brightness values(L*) of the surface, cross-section and powder of the samples, texture analyzer was used to determine the hardness of the samples under different drying conditions. The total starch content was calculated by measuring the contents of amylose and amylopectin in the samples with ultraviolet-visible spectroscopy. 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 different dried samples. Principal component analysis(PCA) was used to comprehensively rank the data of various indicators, and partial least squares-discriminant analysis(PLS-DA) was used to screen differential components with variable importance in the projection(VIP) value>1. Furthermore, the difference between the optimal drying condition for Pinelliae Rhizoma and the traditional sun-drying method was explored by independent samples t-test. ResultsWith the increase of temperature, the color of the intermittently dried samples gradually deepened, while their hardness gradually decreased. Concurrently, the contents of extract, total starch, uridine and adenosine exhibited an upward trend, whereas the contents of uracil, hypoxanthine and inosine displayed a downward trajectory. Compared with the intermittent drying group, the content of extract in the samples subjected to lime-assisted sweating increased. With the increase of lime dose, the hardness and the total content of nucleoside components in the samples showed a downward trend, while the total starch content showed an upward trend. Correlation analysis showed that the comprehensive score of L* was negatively correlated with the contents of uracil, hypoxanthine and inosine, and positively correlated with the contents of uridine, guanosine and adenosine. Hardness was negatively correlated with adenosine content, and positively correlated with the contents of inosine, uracil and hypoxanthine. Through comprehensive consideration and comprehensive score of principal components, the method of 5% lime-mixed sweating for 6 days emerged as the top-ranking approach. Except for the extract, the results of independent samples t-test showed that there was no significant difference between the 5% lime-mixed sweating for 6 days and the traditional sun-drying in terms of other content indicators. ConclusionThe whiteness and firmness of Pinelliae Rhizoma exhibit significant correlations with its chemical composition, while uridine, uracil, guanosine, adenosine and inosine are the key constituents responsible for the quality difference of Pinelliae Rhizoma under different drying conditions. The lime-assisted sweating method 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 and prevents mold contamination, which provides a valuable reference for the standardization of drying conditions and the establishment of quality evaluation criteria for Pinelliae Rhizoma.