Research on pre-processing and storage methods affecting the quality of Ngoc Linh Ginseng medicinal materials

Ngoc Linh ginseng (Panax vietnamensis Ha et Grushv.) is a valuable endemic medicinal plant of Vietnam, renowned for its high content of bioactive saponins and diverse pharmacological activities. This study was conducted to evaluate the effects of different pre-processing methods and storage conditions on the quality of Ngoc Linh ginseng medicinal materials. Four pre-processing treatments, including hot-air drying and heat-pump drying applied to whole roots and sliced roots, were investigated. In addition, three storage methods, namely vacuum packaging at room temperature, vacuum packaging under cool storage (12-14 °C), and conventional storage, were evaluated over a 12-month period. The results showed that all pre-processing methods maintained the characteristic sensory properties of Ngoc Linh ginseng. However, sliced roots subjected to heat-pump drying at 30-35 °C exhibited the shortest drying time (24 ±3 h) and the highest retention of bioactive compounds, with MR2 content reaching 4.02 ±0.03% and total saponin content reaching 13.08 ±0.30%. During storage, total saponin content gradually decreased in all treatments. Nevertheless, vacuum packaging combined with cool storage at 12-14 °C effectively preserved sensory quality, maintained total saponin content (12.1 ±0.2% after 12 months), and resulted in the lowest microbial count (3.5 × 102 CFU/g). The study demonstrated that slicing combined with heat-pump drying at 30-35 °C is an appropriate pre-processing method, while vacuum packaging under cool storage at 12-14 °C is the most suitable storage condition for maintaining the quality and extending the shelf life of Ngoc Linh ginseng medicinal materials.