Quality Characteristics and Criteria for Establishing Standards of Fresh Rehmannia glutinosa ‘Togang’ Produced in Korea

Background: The quality of R. glutinosa can fluctuate based on factors such as cultivation region and harvest timing. This may result in differences in product quality. Therefore, in this study, we aimed to evaluate the quality of fresh R. glutinosa produced in Korea and to establish criteria for establishing standards applicable to the agricultural supply chain.BR/Methods and Results: R. glutinosa ‘Togang’ samples harvested from major production areas were analyzed for rhizome diameter distribution, drying yield, juicing yield, catalpol content, and antioxidant activity. The rhizomes were classified into five categories according to their diameters, and their production ratios were evaluated. The distributions were as follows: 11–15 ㎜, 5–10 ㎜, 16– 20 ㎜, over 20 ㎜ and ≤ 5 ㎜. While there were no significant differences in drying and juicing yields by diameter, the catalpol content was the highest in the 11–15 ? category. The antioxidant content was higher in thin rhizomes with 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activitites following a similar pattern.BR/Conclusion: In this study, we successfully established a quality evaluation and grading system based on the rhizome diameter. The finding can enable farmers and industry professionals to efficiently produce, process, and distribute R. glutinosa, thereby enhancing its industrial applicability and increasing market competitiveness.