The proper storage and preservation of TCM materials are directly linked to their medicinal efficacy and safety. However, during actual storage, issues such as insect infestation, mold growth, loss of aroma, moisture absorption, and rodent damage frequently occur.
Traditional preservation methods involve creating environments unfavorable to pests and mold based on the specific characteristics of the medicinal materials—such as sun-drying and ventilation, airtight storage, low-temperature storage, and chemical fumigation. With the advancement of modern technology, however, Controlled Atmosphere Storage (CAS) has made the storage of TCM materials simpler, more efficient, and more practical.
A common form of controlled atmosphere storage utilizes nitrogen to create an inert atmosphere around TCM materials, facilitating long-term preservation and preventing spoilage or pest infestation. Specifically, nitrogen serves the following functions:
Displacing Oxygen
The primary function of nitrogen filling is to displace atmospheric oxygen, thereby creating a dry, oxygen-free environment. This environment inhibits the oxidation of most organic compounds and the growth of microorganisms, effectively preventing the materials from rotting or becoming moldy.
Inhibiting Pests
In a nitrogen-rich atmosphere, common storage pests and rodents cannot survive due to the lack of oxygen. This not only preserves the physical integrity of the medicinal materials but also reduces the risk of secondary contamination associated with such infestations.
Preserving Medicinal Value
As nitrogen is an inert gas, it does not chemically react with the organic components of the medicinal materials. Consequently, the active ingredients remain intact within the nitrogen atmosphere, and the materials' color, aroma, and medicinal efficacy are better preserved. This extends the shelf life of the materials, allowing them to retain their original therapeutic properties and economic value over a prolonged period.
Technical Advantages of PSA Nitrogen Generation
Among the various nitrogen generation and supply solutions available, PSA (Pressure Swing Adsorption) technology is highly favored due to the following advantages:
1. High Efficiency, Energy Conservation, and Stable Purity
• It employs carbon molecular sieve PSA technology to physically separate nitrogen and oxygen from the air without any chemical reactions. The equipment's energy consumption is relatively moderate compared to other industrial nitrogen generation methods.
• Nitrogen purity can be stabilized between 95% and 99.9995%, with online monitoring instruments provided to track gas purity in real time.
2. Convenient and Smart Operation
The PSA on-site nitrogen generation system features a high degree of automation and simple operation. It supports remote monitoring (via mobile app or cloud platform) and requires no dedicated on-site personnel. Proper sealing ensures maximized nitrogen storage efficiency.
3. Environmentally Friendly and Safe
• PSA air separation technology is a physical separation process conducted at ambient temperature; it involves no chemical pollution. Unlike traditional methods, it eliminates the need for manual stacking, turning, or sun-drying, thereby preventing moisture loss and material damage while effectively preserving the medicinal value of the herbs.
• Nitrogen is an inert, colorless, and odorless gas; contact with the herbs does not compromise their medicinal properties.
Application Forms
• Large Stacks: Primarily suitable for large quantities of herbs stored for long periods in relatively fixed locations.
• Controlled-Atmosphere Containers: Primarily suitable for herbs with regular shapes and compact sizes; ideal for batch trading (spot and forward), rapid turnover, and convenient transport.
• Decoction Piece Bags: Primarily suitable for prepared herbal slices (decoction pieces) used by pharmacies and processing enterprises.
Storage methods involving oxygen reduction and nitrogen filling have emerged as a new, eco-friendly, safe, and reliable technology for preserving medicinal herbs. Furthermore, this technology provides the technical foundation and support for traceability, financial warehousing, electronic trading, and futures trading within the industry.