Abstract:[Objective] This study aims to investigate the effects of steaming-drying cycles on the quality changes of Polygonati rhizoma and optimize the processing technology to enhance its application value.[Method] Slices of Polygonati rhizoma processed by 0~5 steaming-drying cycles were prepared. The drying rate and drying kinetics during the drying stage after each cycle were analyzed, and a drying model was fitted. Changes in color difference, appearance, hardness, and mass fractions of polysaccharides, reducing sugars, polyphenols, flavonoids, saponins, and calcium oxalate raphides were measured.[Result] The number of steaming-drying cycles significantly affected the quality of Polygonati rhizoma. The drying rate decreased as the drying time increased, conforming to the Modified Page model, while the water activity reduced. As the number of steaming-drying cycles increased, the sample microstructure was disrupted, which promoted the release of active substances. The mass fractions of saponins, flavonoids, and polyphenols in the C4 group increased by 161.28%, 67.15%, and 417.93%, respectively, compared with those in the C0 group. Non-enzymatic browning reactions led to increased color difference and significantly decreased mass fraction of calcium oxalate raphides, which reduced oral irritation. Although the mass fraction of polysaccharides declined during processing, the C4 group exhibited 5.15% higher polysaccharide retention rate and 141.63% lower hardness than the C5 group.[Conclusion] The processing with steaming-drying cycles significantly improves the quality of Polygonati rhizoma. The processing method of four steaming-drying cycles demonstrates outstanding performance in releasing active substances, preserving polysaccharides, and controlling hardness, showing broad application prospects.
